diff --git a/doc/grammar.bnf b/doc/grammar.bnf
index f8abd01..12db630 100644
--- a/doc/grammar.bnf
+++ b/doc/grammar.bnf
@@ -1,14 +1,18 @@
 ROOT ::= EXPR*
 EXPR ::= 
-| TERM
+| OR
 | ASSERT
 ASSERT ::= assert EXPR eq EXPR
+OR ::= AND (or AND)*
+AND ::= TERM (and TERM)*
 TERM ::= FACTOR ((add|sub) FACTOR)*
 FACTOR ::= USUB ((mul|div|mod) USUB)*
-USUB ::= sub* POW 
+USUB ::= sub* NOT 
+NOT ::= not* POW
 POW ::= LITERAL (pow LITERAL)?
 LITERAL ::=
 | BUILTIN 
 | opar EXPR cpar
 BUILTIN ::=
 | int
+| bool
diff --git a/features/bool.sk b/features/bool.sk
new file mode 100644
index 0000000..533b169
--- /dev/null
+++ b/features/bool.sk
@@ -0,0 +1,15 @@
+assert true eq true
+assert false eq false
+
+assert not true eq false
+assert not false eq true
+
+assert true and true eq true
+assert true and false eq false
+assert false and true eq false
+assert false and false eq false
+
+assert true or true eq true
+assert true or false eq true
+assert false or true eq true
+assert false or false eq false
diff --git a/lib/include/compiler.h b/lib/include/compiler.h
index 5f4c0c6..7db4ae3 100644
--- a/lib/include/compiler.h
+++ b/lib/include/compiler.h
@@ -18,5 +18,19 @@ void compiler_compile(struct compiler* self,
 void compiler_compile_children(struct compiler* self,
                                struct node* node,
                                struct prog* prog);
+
+void compiler_compile_value(struct compiler* self,
+                            struct node* node,
+                            struct prog* prog,
+                            TypeKind type,
+                            union val val);
+
+void compiler_compile_and(struct compiler* self,
+                          struct node* node,
+                          struct prog* prog);
+
+void compiler_compile_or(struct compiler* self,
+                          struct node* node,
+                          struct prog* prog);
 #endif
 
diff --git a/lib/include/node.h b/lib/include/node.h
index 0857517..c01263c 100644
--- a/lib/include/node.h
+++ b/lib/include/node.h
@@ -8,7 +8,9 @@ G(NODE_ROOT), \
 G(NODE_INT), \
 G(NODE_ADD), G(NODE_SUB), G(NODE_MUL),\
 G(NODE_DIV), G(NODE_POW), G(NODE_MOD),\
-G(NODE_USUB), G(NODE_ASSERT_EQ)
+G(NODE_USUB), G(NODE_ASSERT_EQ), \
+G(NODE_BOOL), G(NODE_AND), G(NODE_OR), \
+G(NODE_NOT)
 
 SK_ENUM_H(NodeKind, NODE_KIND);
 
diff --git a/lib/include/parser.h b/lib/include/parser.h
index ec79eb2..7d09a7d 100644
--- a/lib/include/parser.h
+++ b/lib/include/parser.h
@@ -20,9 +20,12 @@ struct node* parser_try_parse(struct parser* self);
 struct node* parser_try_root(struct parser* self);
 struct node* parser_try_expr(struct parser* self);
 struct node* parser_try_assert(struct parser* self);
+struct node* parser_try_or(struct parser* self);
+struct node* parser_try_and(struct parser* self);
 struct node* parser_try_term(struct parser* self);
 struct node* parser_try_factor(struct parser* self);
 struct node* parser_try_usub(struct parser* self);
+struct node* parser_try_not(struct parser* self);
 struct node* parser_try_pow(struct parser* self);
 struct node* parser_try_literal(struct parser* self);
 struct node* parser_try_builtin(struct parser* self);
diff --git a/lib/include/prog.h b/lib/include/prog.h
index fe14679..d230327 100644
--- a/lib/include/prog.h
+++ b/lib/include/prog.h
@@ -9,7 +9,9 @@
 G(OP_PUSH), \
 G(OP_ADD), G(OP_SUB), G(OP_MUL), \
 G(OP_DIV), G(OP_MOD), G(OP_POW), \
-G(OP_USUB), G(OP_ASSERT_EQ)
+G(OP_USUB), G(OP_ASSERT_EQ), \
+G(OP_NOT), G(OP_AND), G(OP_OR), \
+G(OP_BR), G(OP_BRF)
 
 SK_ENUM_H(Opcode, OPCODE);
 
diff --git a/lib/include/state.h b/lib/include/state.h
index f185d3a..0dfa780 100644
--- a/lib/include/state.h
+++ b/lib/include/state.h
@@ -44,7 +44,13 @@ struct value* state_try_get_value(struct state* self, SK value);
 
 SK state_pop(struct state* self);
 
+SK state_push(struct state* self, 
+              TypeKind type, 
+              union val val, 
+              int line);
+
 SK state_push_int(struct state* self, int integer, int line);
+SK state_push_bool(struct state* self, bool boolean, int line);
 
 SK state_add(struct state* self);
 SK state_sub(struct state* self);
@@ -54,4 +60,8 @@ SK state_div(struct state* self);
 SK state_mod(struct state* self);
 SK state_pow(struct state* self);
 
+SK state_and(struct state* self);
+SK state_or(struct state* self);
+SK state_not(struct state* self);
+
 #endif
diff --git a/lib/include/token.h b/lib/include/token.h
index ae26819..ca50d2e 100644
--- a/lib/include/token.h
+++ b/lib/include/token.h
@@ -9,7 +9,9 @@ G(TOKEN_INT), \
 G(TOKEN_ADD), G(TOKEN_SUB), \
 G(TOKEN_MUL), G(TOKEN_DIV), G(TOKEN_MOD), \
 G(TOKEN_POW), G(TOKEN_OPAR), G(TOKEN_CPAR), \
-G(TOKEN_ASSERT), G(TOKEN_ASSERT_EQ)
+G(TOKEN_ASSERT), G(TOKEN_ASSERT_EQ), \
+G(TOKEN_BOOL), G(TOKEN_AND), G(TOKEN_OR), \
+G(TOKEN_NOT)
 
 SK_ENUM_H(TokenKind, TOKEN_KIND);
 
diff --git a/lib/include/value.h b/lib/include/value.h
index 414638c..150d3ce 100644
--- a/lib/include/value.h
+++ b/lib/include/value.h
@@ -5,13 +5,14 @@
 #include "node.h"
 
 #define TYPE_KIND(G) \
-G(TYPE_INT)
+G(TYPE_INT), G(TYPE_BOOL)
 
 SK_ENUM_H(TypeKind, TYPE_KIND);
 
 union val
 {
     int integer;
+    bool boolean;
 };
 
 struct value
diff --git a/lib/src/compiler.c b/lib/src/compiler.c
index e98a6d4..851e270 100644
--- a/lib/src/compiler.c
+++ b/lib/src/compiler.c
@@ -29,19 +29,37 @@ void compiler_compile(struct compiler* self,
             }
         } break;
 
+        case NODE_NOT: {
+            compiler_compile_children(self, node, prog);
+            prog_add_instr(prog, OP_NOT, SK_NO_PARAM);
+        } break;
+
+        case NODE_AND: {
+            compiler_compile_and(self, node, prog);
+        } break;
+
+        case NODE_OR: {
+            compiler_compile_or(self, node, prog);
+        } break;
+
         case NODE_ASSERT_EQ: {
             compiler_compile_children(self, node, prog);
             prog_add_instr(prog, OP_ASSERT_EQ, SK_NO_PARAM);
         } break;
 
+        case NODE_BOOL: {
+            union val val;
+            val.boolean =
+                strcmp(node->token->value, "true") == 0;
+            compiler_compile_value(self, node, prog, TYPE_BOOL,
+                                   val);
+        } break;
+
         case NODE_INT: {
-            struct value* value = malloc(sizeof(struct value));
             union val val;
             val.integer = atoi(node->token->value);
-            value_init(value, TYPE_INT, val, node->token->line);
-
-            size_t idx = prog_add_constant(prog, value);
-            prog_add_instr(prog, OP_PUSH, idx);
+            compiler_compile_value(self, node, prog, TYPE_INT,
+                                   val);
         } break;
 
         case NODE_ADD: {
@@ -101,3 +119,101 @@ void compiler_compile_children(struct compiler* self,
         compiler_compile(self, child, prog);
     }
 }
+
+
+void compiler_compile_value(struct compiler* self,
+                            struct node* node,
+                            struct prog* prog,
+                            TypeKind type,
+                            union val val)
+{
+    (void) self;
+    struct value* value = malloc(sizeof(struct value));
+    value_init(value, type, val, node->token->line);
+
+    size_t idx = prog_add_constant(prog, value);
+    prog_add_instr(prog, OP_PUSH, idx);
+}
+
+void compiler_compile_and(struct compiler* self,
+                          struct node* node,
+                          struct prog* prog)
+{
+    assert(self);
+    assert(node);
+    assert(prog);
+
+    struct vec to_false;
+    vec_init(&to_false);
+
+    for (size_t i =0; i<node->children.size; i++)
+    {
+        struct node* child = node->children.data[i];
+        compiler_compile(self, child, prog);
+        size_t brf = prog_add_instr(prog, OP_BRF, 0); // to false
+        vec_push(&to_false, (void*) brf);
+    }
+
+    union val tval;
+    tval.boolean = true;
+    compiler_compile_value(self, node, prog, TYPE_BOOL, tval);
+    size_t to_end = prog_add_instr(prog, OP_BR, 0);
+
+    union val fval;
+    fval.boolean = false;
+    size_t false_point = prog->opcodes.size;
+    compiler_compile_value(self, node, prog, TYPE_BOOL, fval);
+
+    size_t end_point = prog->opcodes.size;
+    ((size_t*)prog->params.data)[to_end] = end_point;
+
+    for (size_t i=0; i<to_false.size; i++)
+    {
+        ((size_t*)prog->params.data)[(size_t)
+            to_false.data[i]] = false_point;
+    }
+
+    vec_free(&to_false);
+}
+
+void compiler_compile_or(struct compiler* self,
+                         struct node* node,
+                         struct prog* prog)
+{
+    assert(self);
+    assert(node);
+    assert(prog);
+
+    struct vec to_true;
+    vec_init(&to_true);
+
+    for (size_t i =0; i<node->children.size; i++)
+    {
+        struct node* child = node->children.data[i];
+        compiler_compile(self, child, prog);
+        prog_add_instr(prog, OP_NOT, 0);
+        size_t brf = prog_add_instr(prog, OP_BRF, 0); // to true
+        vec_push(&to_true, (void*) brf);
+    }
+
+    union val fval;
+    fval.boolean = false;
+    compiler_compile_value(self, node, prog, TYPE_BOOL, fval);
+    size_t to_end = prog_add_instr(prog, OP_BR, 0);
+
+    union val tval;
+    tval.boolean = true;
+    size_t true_point = prog->opcodes.size;
+    compiler_compile_value(self, node, prog, TYPE_BOOL, tval);
+
+    size_t end_point = prog->opcodes.size;
+    ((size_t*)prog->params.data)[to_end] = end_point;
+
+    for (size_t i=0; i<to_true.size; i++)
+    {
+        ((size_t*)prog->params.data)[(size_t)
+            to_true.data[i]] = true_point;
+    }
+
+    vec_free(&to_true);
+}
diff --git a/lib/src/exec.c b/lib/src/exec.c
index 7af42db..fd676b2 100644
--- a/lib/src/exec.c
+++ b/lib/src/exec.c
@@ -49,7 +49,7 @@ void exec_execute(struct exec* self,
                     str_init(&rstr);
                     value_str(right, &rstr);
 
-                    errors_push(left->line, 
+                    errors_push(left->line,
                                 "assertion failed"
                                 "\n\texpected: %s"
                                 "\n\tgot: %s",
@@ -73,6 +73,15 @@ void exec_execute(struct exec* self,
                             constant->line
                         );
                     } break;
+
+                    case TYPE_BOOL: {
+                        state_push_bool(
+                            state,
+                            constant->val.boolean,
+                            constant->line
+                        );
+                    } break;
+
                     default: {
                         fprintf(stderr, "cannot push value '%s'\n",
                                 TypeKindStr[constant->type]);
@@ -117,6 +126,41 @@ void exec_execute(struct exec* self,
                 self->pc++;
             } break;
 
+            case OP_NOT: {
+                state_not(state);
+                self->pc++;
+            } break;
+
+            case OP_AND: {
+                state_and(state);
+                self->pc++;
+            } break;
+
+            case OP_OR: {
+                state_or(state);
+                self->pc++;
+            } break;
+
+            case OP_BR: {
+                self->pc = param;
+            } break;
+
+            case OP_BRF: {
+                SK addr = state_pop(state);
+                bool val =
+                    state_try_get_value(state, addr)->val.boolean;
+
+                if (!val)
+                {
+                    self->pc = param;
+                }
+                else
+                {
+                    self->pc++;
+                }
+
+            } break;
+
             default: {
                 fprintf(stderr, "cannot execute opcode '%s'\n",
                         OpcodeStr[opcode]);
diff --git a/lib/src/lexer.c b/lib/src/lexer.c
index d2d951b..8c6e2a9 100644
--- a/lib/src/lexer.c
+++ b/lib/src/lexer.c
@@ -122,6 +122,11 @@ struct token* lexer_try_new_next(struct lexer* self)
     SK_SCAN_TEXT(")", TOKEN_CPAR);
     SK_SCAN_KEYWORD("assert", TOKEN_ASSERT, NULL);
     SK_SCAN_KEYWORD("eq", TOKEN_ASSERT_EQ, NULL);
+    SK_SCAN_KEYWORD("true", TOKEN_BOOL, "true");
+    SK_SCAN_KEYWORD("false", TOKEN_BOOL, "false");
+    SK_SCAN_KEYWORD("and", TOKEN_AND, NULL);
+    SK_SCAN_KEYWORD("or", TOKEN_OR, NULL);
+    SK_SCAN_KEYWORD("not", TOKEN_NOT, NULL);
 
     if (self->context.cursor < self->len)
     {
diff --git a/lib/src/parser.c b/lib/src/parser.c
index ffa4b55..0a6b6b1 100644
--- a/lib/src/parser.c
+++ b/lib/src/parser.c
@@ -73,7 +73,7 @@ struct node* parser_try_expr(struct parser* self)
         return SK_TRY(parser_try_assert);
     }
 
-    return SK_TRY(parser_try_term);
+    return SK_TRY(parser_try_or);
 }
 
 struct node* parser_try_assert(struct parser* self)
@@ -99,11 +99,11 @@ struct node* parser_try_assert(struct parser* self)
 
     lexer_consume_next(&self->lexer);
     struct node* rhs = SK_TRY(parser_try_expr);
-    if (!rhs) 
+    if (!rhs)
     {
         token_free(tok);
         free(tok);
-        return NULL; 
+        return NULL;
     }
 
     struct node* node = malloc(sizeof(struct node));
@@ -113,6 +113,66 @@ struct node* parser_try_assert(struct parser* self)
     return node;
 }
 
+struct node* parser_try_or(struct parser* self)
+{
+    assert(self);
+    struct node* lhs = SK_TRY(parser_try_and);
+    if (!lhs) { return NULL; }
+
+    while (lexer_next_is(&self->lexer, TOKEN_OR))
+    {
+        struct node* node = malloc(sizeof(struct node));
+        node_init(node, NODE_OR, lexer_try_new_next(
+            &self->lexer
+        ));
+
+        node_push_new_child(node, lhs);
+        struct node* rhs = SK_TRY(parser_try_and);
+
+        if (!rhs)
+        {
+            node_free(node);
+            free(node);
+            return NULL;
+        }
+
+        node_push_new_child(node, rhs);
+        lhs = node;
+    }
+
+    return lhs;
+}
+
+struct node* parser_try_and(struct parser* self)
+{
+    assert(self);
+    struct node* lhs = SK_TRY(parser_try_term);
+    if (!lhs) { return NULL; }
+
+    while (lexer_next_is(&self->lexer, TOKEN_AND))
+    {
+        struct node* node = malloc(sizeof(struct node));
+        node_init(node, NODE_AND, lexer_try_new_next(
+            &self->lexer
+        ));
+
+        node_push_new_child(node, lhs);
+        struct node* rhs = SK_TRY(parser_try_term);
+
+        if (!rhs)
+        {
+            node_free(node);
+            free(node);
+            return NULL;
+        }
+
+        node_push_new_child(node, rhs);
+        lhs = node;
+    }
+
+    return lhs;
+}
+
 struct node* parser_try_term(struct parser* self)
 {
     assert(self);
@@ -225,6 +285,33 @@ struct node* parser_try_usub(struct parser* self)
         return node;
     }
 
+    return SK_TRY(parser_try_not);
+}
+
+struct node* parser_try_not(struct parser* self)
+{
+    assert(self);
+
+    if (lexer_next_is(&self->lexer, TOKEN_NOT))
+    {
+        struct node* node = malloc(sizeof(struct node));
+        node_init(node, NODE_NOT, lexer_try_new_next(
+            &self->lexer
+        ));
+
+        struct node* child = SK_TRY(parser_try_not);
+
+        if (!child)
+        {
+            node_free(node);
+            free(node);
+            return NULL;
+        }
+
+        node_push_new_child(node, child);
+        return node;
+    }
+
     return SK_TRY(parser_try_pow);
 }
 
@@ -290,6 +377,17 @@ struct node* parser_try_literal(struct parser* self)
 
 struct node* parser_try_builtin(struct parser* self)
 {
+    if (lexer_next_is(&self->lexer, TOKEN_BOOL))
+    {
+        struct node* node = malloc(sizeof(struct node));
+
+        node_init(node,
+                  NODE_BOOL,
+                  lexer_try_new_next(&self->lexer));
+
+        return node;
+    }
+
     if (lexer_next_is(&self->lexer, TOKEN_INT))
     {
         struct node* node = malloc(sizeof(struct node));
diff --git a/lib/src/state.c b/lib/src/state.c
index 1985d47..e911ab5 100644
--- a/lib/src/state.c
+++ b/lib/src/state.c
@@ -107,14 +107,15 @@ SK state_pop(struct state* self)
     return value;
 }
 
-SK state_push_int(struct state* self, int integer, int line)
+SK state_push(struct state* self,
+              TypeKind type,
+              union val val,
+              int line)
 {
     assert(self);
 
     struct value* value = malloc(sizeof(struct value));
-    union val val;
-    val.integer = integer;
-    value_init(value, TYPE_INT, val, line);
+    value_init(value, type, val, line);
 
     struct frame* frame = state_frame(self);
     struct local* local = malloc(sizeof(struct local));
@@ -125,8 +126,26 @@ SK state_push_int(struct state* self, int integer, int line)
 
     self->addr++;
     return self->addr - 1;
+}
+
+SK state_push_int(struct state* self, int integer, int line)
+{
+    assert(self);
+
+    union val val;
+    val.integer = integer;
+    return state_push(self, TYPE_INT, val, line);
  }
 
+SK state_push_bool(struct state* self, bool boolean, int line)
+{
+    assert(self);
+
+    union val val;
+    val.boolean = boolean;
+    return state_push(self, TYPE_BOOL, val, line);
+}
+
 SK state_add(struct state* self)
 {
     SK rhs = state_pop(self);
@@ -229,3 +248,46 @@ SK state_pow(struct state* self)
         left->line
     );
 }
+
+SK state_and(struct state* self)
+{
+    SK rhs = state_pop(self);
+    SK lhs = state_pop(self);
+
+    struct value* left = state_try_get_value(self, lhs);
+    struct value* right = state_try_get_value(self, rhs);
+
+    return state_push_bool(
+        self,
+        left->val.boolean && right->val.boolean,
+        left->line
+    );
+}
+
+SK state_or(struct state* self)
+{
+    SK rhs = state_pop(self);
+    SK lhs = state_pop(self);
+
+    struct value* left = state_try_get_value(self, lhs);
+    struct value* right = state_try_get_value(self, rhs);
+
+    return state_push_bool(
+        self,
+        left->val.boolean || right->val.boolean,
+        left->line
+    );
+}
+
+SK state_not(struct state* self)
+{
+    SK lhs = state_pop(self);
+
+    struct value* left = state_try_get_value(self, lhs);
+
+    return state_push_bool(
+        self,
+        !left->val.boolean,
+        left->line
+    );
+}
diff --git a/lib/src/value.c b/lib/src/value.c
index e3d29b0..bc4406b 100644
--- a/lib/src/value.c
+++ b/lib/src/value.c
@@ -46,6 +46,11 @@ void value_str(struct value* self, struct str* dest)
         case TYPE_INT: {
             str_format(dest, "%d", self->val.integer);
         } break;
+
+        case TYPE_BOOL: {
+            str_format(dest, "%s",
+                       self->val.boolean ? "true" : "false");
+        } break;
         default: {
             fprintf(stderr, "cannot get value string of '%s'\n",
                     TypeKindStr[self->type]);
diff --git a/tests/lexer.h b/tests/lexer.h
index 58228fb..a6c42b0 100644
--- a/tests/lexer.h
+++ b/tests/lexer.h
@@ -26,7 +26,7 @@ static void test_lexer(char const* source, int count, ...)
             fprintf(stderr, "%s != %s\n", oracle, tok_str.value);
         }
 
-        CU_ASSERT_STRING_EQUAL(tok_str.value, oracle);
+        CU_ASSERT_STRING_EQUAL_FATAL(tok_str.value, oracle);
         str_free(&tok_str);
         token_free(tok);
         free(tok);
@@ -60,11 +60,22 @@ static void test_lexer_assert()
     );
 }
 
+static void test_lexer_bool()
+{
+    test_lexer("true false and or not", 5,
+               "BOOL[true]",
+               "BOOL[false]",
+               "AND",
+               "OR",
+               "NOT"
+    );
+}
 void register_lexer()
 {
     CU_pSuite suite = CU_add_suite("Lexer", 0, 0);
     CU_add_test(suite, "Integers", test_lexer_int);
     CU_add_test(suite, "Assertions", test_lexer_assert);
+    CU_add_test(suite, "Booleans", test_lexer_bool);
 }
 
 #endif
diff --git a/tests/parser.h b/tests/parser.h
index 4fc313a..3340ce8 100644
--- a/tests/parser.h
+++ b/tests/parser.h
@@ -44,15 +44,32 @@ static void test_parser_int()
 
 static void test_parser_assert()
 {
-    test_parser("ROOT(ASSERT_EQ(INT[32],INT[12]))", 
+    test_parser("ROOT(ASSERT_EQ(INT[32],INT[12]))",
                 " assert 32 eq 12 ");
 }
 
+static void test_parser_bool()
+{
+    test_parser("ROOT(BOOL[true])",
+                "true");
+
+    test_parser("ROOT(NOT(BOOL[false]))",
+                "not false");
+
+    test_parser("ROOT(OR(AND(NOT(BOOL[false]),BOOL[true]),"
+                "BOOL[false]))",
+                "not false and true or false");
+
+    test_parser("ROOT(AND(NOT(BOOL[false]),OR(BOOL[true],"
+                "BOOL[false])))",
+                "not false and (true or false)");
+}
 void register_parser()
 {
     CU_pSuite suite = CU_add_suite("Parser", 0, 0);
     CU_add_test(suite, "Integers", test_parser_int);
     CU_add_test(suite, "Assertions", test_parser_assert);
+    CU_add_test(suite, "Booleans", test_parser_bool);
 }
 
 #endif