diff --git a/src/boolean/__test__/type.spec.js b/src/boolean/__test__/type.spec.js
new file mode 100644
index 0000000..ad294a7
--- /dev/null
+++ b/src/boolean/__test__/type.spec.js
@@ -0,0 +1,25 @@
+import assert from 'assert'
+import math from '#nanomath'
+import {Type} from '#core/Type.js'
+
+const boolean = math.boolean
+
+describe('boolean type functions', () => {
+   it('properly converts to boolean', () => {
+      assert.strictEqual(boolean(false), false)
+      assert.strictEqual(boolean(true), true)
+      assert.strictEqual(boolean(0), false)
+      assert.strictEqual(boolean(-0), false)
+      assert.strictEqual(boolean(NaN), false)
+      assert.strictEqual(boolean(Infinity), true)
+      assert.strictEqual(boolean(1e-30), true)
+      assert.strictEqual(boolean(undefined), false)
+      assert.strictEqual(boolean(), false)
+      assert.strictEqual(boolean(math.types.NumberT), true)
+   })
+   it('converts any type to boolean', () => {
+      for (const T in math.types) {
+         if (T instanceof Type) assert(boolean.resolve([T]))
+      }
+   })       
+})
diff --git a/src/boolean/type.js b/src/boolean/type.js
new file mode 100644
index 0000000..169a207
--- /dev/null
+++ b/src/boolean/type.js
@@ -0,0 +1,14 @@
+import {BooleanT} from './BooleanT.js'
+import {onType} from '#core/helpers.js'
+import {Returns, Type, TypeOfTypes, Undefined} from '#core/Type.js'
+import {NumberT} from '#number/NumberT.js'
+
+const bool = f => Returns(BooleanT, f)
+
+export const boolean = onType(
+   BooleanT, bool(p => p),
+   NumberT, bool(a => !!a),
+   TypeOfTypes, bool(() => true),
+   Undefined, bool(() => false),
+   [], bool(() => false)
+)