diff --git a/icepick/icepick-tests.ts b/icepick/icepick-tests.ts
new file mode 100644
index 0000000000..350e5f2dc8
--- /dev/null
+++ b/icepick/icepick-tests.ts
@@ -0,0 +1,177 @@
+/// <reference path="icepick.d.ts" />
+/// <reference path="../underscore/underscore.d.ts" />
+
+
+import i = require("icepick");
+
+"use strict"; // so attempted modifications of frozen objects will throw errors
+
+// freeze(collection)
+{
+    let coll = {
+        a: "foo",
+        b: [1, 2, 3],
+        c: {
+            d: "bar"
+        }
+    };
+
+    i.freeze(coll);
+}
+
+// thaw(collection)
+class Foo {}
+
+{
+    let coll = i.freeze({ a: "foo", b: [1, 2, 3], c: { d: "bar" }, e: new Foo() });
+    let thawed = i.thaw(coll);
+}
+
+// assoc(collection, key, value)
+{
+    let coll = { a: 1, b: 2 };
+    let newColl = i.assoc(coll, "b", 3); // {a: 1, b: 3}
+
+    let arr = ["a", "b", "c"];
+    let newArr = i.assoc(arr, 2, "d"); // ["a", "b", "d"]
+}
+
+// alias: set(collection, key, value)
+{
+    let coll = { a: 1, b: 2 };
+    let newColl = i.set(coll, "b", 3); // {a: 1, b: 3}
+
+    let arr = ["a", "b", "c"];
+    let newArr = i.set(arr, 2, "d"); // ["a", "b", "d"]
+}
+
+// dissoc(collection, key)
+{
+    let coll = { a: 1, b: 2, c: 3 };
+    let newColl = i.dissoc(coll, "b"); // {a: 1, c: 3}
+
+    let arr = ["a", "b", "c"];
+    let newArr = i.dissoc(arr, 2); // ["a", , "c"]
+}
+
+// alias: unset(collection, key)
+{
+    let coll = { a: 1, b: 2, c: 3 };
+    let newColl = i.unset(coll, "b"); // {a: 1, c: 3}
+
+    let arr = ["a", "b", "c"];
+    let newArr = i.unset(arr, 2); // ["a", , "c"]
+}
+
+// assocIn(collection, path, value)
+{
+    let coll = {
+        a: "foo",
+        b: [1, 2, 3],
+        c: {
+            d: "bar"
+        }
+    };
+
+    let newColl = i.assocIn(coll, ["c", "d"], "baz");
+
+    let coll2 = {};
+    let newColl2 = i.assocIn(coll2, ["a", "b", "c"], 1);
+}
+
+// alias: setIn(collection, path, value)
+{
+    let coll = {
+        a: "foo",
+        b: [1, 2, 3],
+        c: {
+            d: "bar"
+        }
+    };
+
+    let newColl = i.setIn(coll, ["c", "d"], "baz");
+
+    let coll2 = {};
+    let newColl2 = i.setIn(coll2, ["a", "b", "c"], 1);
+}
+
+// getIn(collection, path)
+{
+    let coll = i.freeze([
+        { a: 1 },
+        { b: 2 }
+    ]);
+
+    let result = i.getIn(coll, [1, "b"]); // 2
+}
+
+// updateIn(collection, path, callback)
+{
+    let coll = i.freeze([
+        { a: 1 },
+        { b: 2 }
+    ]);
+
+    let newColl = i.updateIn(coll, [1, "b"], function(val: number) {
+        return val * 2;
+    }); // [ {a: 1}, {b: 4} ]
+}
+
+// assign(coll1, coll2, ...)
+{
+    let obj1 = { a: 1, b: 2, c: 3 };
+    let obj2 = { c: 4, d: 5 };
+
+    let result = i.assign(obj1, obj2); // {a: 1, b: 2, c: 4, d: 5}
+}
+
+// merge(target, source)
+{
+    let defaults = { a: 1, c: { d: 1, e: [1, 2, 3], f: { g: 1 } } };
+    let obj = { c: { d: 2, e: [2], f: null as any } };
+
+    let result1 = i.merge(defaults, obj); // {a: 1, c: {d: 2, e: [2]}, f: null}
+
+    let obj2 = { c: { d: 2 } };
+    let result2 = i.merge(result1, obj2);
+
+    (result1 === result2); // true
+}
+
+// arrays
+{
+    var a = [1];
+    a = i.push(a, 2); // [1, 2];
+    a = i.unshift(a, 0); // [0, 1, 2];
+    a = i.pop(a); // [0, 1];
+    a = i.shift(a); // [1];
+}
+{
+    i.map(function(v) { return v * 2 }, [1, 2, 3]); // [2, 4, 6]
+
+    var removeEvens = _.partial(i.filter, function(v: number) { return v % 2; });
+
+    removeEvens([1, 2, 3]); // [1, 3]
+}
+{
+    var arr = i.freeze([{ a: 1 }, { b: 2 }]);
+
+    //ECMAScript 2015
+    //arr.find(function(item) { return item.b != null; }); // {b: 2} 
+}
+
+// chain(coll) - not defined
+{
+    let o = {
+        a: [1, 2, 3],
+        b: { c: 1 },
+        d: 4
+    };
+
+    let result = i.chain(o)
+        .assocIn(["a", 2], 4)
+        .merge({ b: { c: 2, c2: 3 } })
+        .assoc("e", 2)
+        .dissoc("d")
+        .value();
+}
diff --git a/icepick/icepick.d.ts b/icepick/icepick.d.ts
new file mode 100644
index 0000000000..85bbf0ae3d
--- /dev/null
+++ b/icepick/icepick.d.ts
@@ -0,0 +1,72 @@
+// Type definitions for icepick v1.1.0
+// Project: https://github.com/aearly/icepick
+// Definitions by: Nathan Brown <https://github.com/ngbrown>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+declare module "icepick" {
+  export function freeze<T>(collection: T): T;
+  export function thaw<T>(collection: T): T;
+  export function assoc<T>(collection: T, key: number | string, value: any): T;
+  export function dissoc<T>(collection: T, key: number | string): T;
+  export function assocIn<T>(collection: T, path: Array<number | string>, value: any): T;
+  export function getIn<Result>(collection: any, path: Array<number | string>): Result;
+  export function updateIn<T, V>(collection: T, path: Array<number | string>, callback: (value: V) => V): T;
+
+  export {assoc as set};
+  export {dissoc as unset};
+  export {assocIn as setIn};
+
+  export function assign<T>(target: T): T;
+  export function assign<T, S1>(target: T, source1: S1): (T & S1);
+  export function assign<T, S1, S2>(target: T, s1: S1, s2: S2): (T & S1 & S2);
+  export function assign<T, S1, S2, S3>(target: T, s1: S1, s2: S2, s3: S3): (T & S1 & S2 & S3);
+  export function assign<T, S1, S2, S3, S4>(target: T, s1: S1, s2: S2, s3: S3, s4: S4): (T & S1 & S2 & S3 & S4);
+
+  export {assign as extend};
+
+  export function merge<T, S1>(target: T, source: S1): (T & S1);
+
+  export function push<T>(array: T[], element: T): T[];
+  export function pop<T>(array: T[]): T[];
+  export function shift<T>(array: T[]): T[];
+  export function unshift<T>(array: T[], element: T): T[];
+  export function reverse<T>(array: T[]): T[];
+  export function sort<T>(array: T[], compareFunction?: (a:T, b:T) => number): T[];
+  export function splice<T>(array: T[], start: number, deleteCount: number, ...items: T[]): T[];
+  export function slice<T>(array: T[], begin?: number, end?: number): T[];
+
+  export function map<T, U>(fn: (value: T) => U, array: T[]): U[];
+  export function filter<T>(fn: (value: T) => boolean, array: T[]): T[];
+
+  interface IcepickWrapper<T> {
+    value(): T;
+
+    freeze(): IcepickWrapper<T>;
+    thaw(): IcepickWrapper<T>;
+
+    assoc(key: number | string, value: any): IcepickWrapper<T>;
+    set(key: number | string, value: any): IcepickWrapper<T>;
+
+    dissoc(key: number | string): IcepickWrapper<T>;
+    unset(key: number | string): IcepickWrapper<T>;
+
+    assocIn(path: Array<number | string>, value: any): IcepickWrapper<T>;
+    setIn(path: Array<number | string>, value: any): IcepickWrapper<T>;
+
+    getIn<Result>(collection: any, path: Array<number | string>): IcepickWrapper<Result>;
+    updateIn<T, V>(collection: T, path: Array<number | string>, callback: (value: V) => V): IcepickWrapper<T>;
+
+    assign<S1>(source1: S1): IcepickWrapper<T & S1>;
+    assign<S1, S2>(s1: S1, s2: S2): IcepickWrapper<T & S1 & S2>;
+    assign<S1, S2, S3>(s1: S1, s2: S2, s3: S3): IcepickWrapper<T & S1 & S2 & S3>;
+    assign<S1, S2, S3, S4>(s1: S1, s2: S2, s3: S3, s4: S4): IcepickWrapper<T & S1 & S2 & S3 & S4>;
+    extend<S1>(source1: S1): IcepickWrapper<T & S1>;
+    extend<S1, S2>(s1: S1, s2: S2): IcepickWrapper<T & S1 & S2>;
+    extend<S1, S2, S3>(s1: S1, s2: S2, s3: S3): IcepickWrapper<T & S1 & S2 & S3>;
+    extend<S1, S2, S3, S4>(s1: S1, s2: S2, s3: S3, s4: S4): IcepickWrapper<T & S1 & S2 & S3 & S4>;
+
+    merge<S1>(source: S1): IcepickWrapper<T & S1>;
+  }
+
+  export function chain<T>(target: T): IcepickWrapper<T>;
+}