diff --git a/knockout.es5/knockout.es5-tests.ts b/knockout.es5/knockout.es5-tests.ts
new file mode 100644
index 000000000..f8faf9529
--- /dev/null
+++ b/knockout.es5/knockout.es5-tests.ts
@@ -0,0 +1,77 @@
+/// <reference path="knockout.es5.d.ts" />
+
+var empty = {},
+    obj = { a: 'string', b: 123, c: true, d: empty },
+    observable = ko.observable(123),
+    computed = ko.computed(function () { return observable() + 1; }),
+    model = { prop: 100 },
+    notifiedValues = [];
+
+
+// Basic properties
+ko.track(empty);
+ko.track(null);
+ko.track(obj);
+ko.track({ a: 1 });
+ko.track({ prop: observable });
+ko.track({ prop: computed });
+ko.track({ a: 1, b: 2, c: 3 }, null);
+ko.track({ a: 1, b: 2, c: 3 }, []);
+ko.track({ a: 1, b: 2, c: 3 }, ['a', 'c']);
+ko.track({ prop: observable }, ['prop']);
+ko.track({ prop: computed }, ['prop']);
+ko.track(null, null);
+ko.track(model);
+
+// Computed properties
+ko.defineProperty(model, 'propPlusOne', () => { return model.prop + 1; });
+ko.defineProperty(model, 'propOne', { get: function () { return 1; } });
+ko.defineProperty(model, 'propPlusOne', { get: () => model.prop++, set: (value) => model.prop = value - 1 });
+
+// Utility functions
+ko.getObservable(model, 'propPlusOne').subscribe((newValue) => notifiedValues.push(newValue));
+
+
+// Simple usage example
+class OrderLine {
+    subtotal: string;
+
+    constructor(public item: any, public price: number, public quantity: number) {
+        // Instead of declaring ko.observable properties, we just have one call to ko.track 
+        ko.track(this);
+
+        // Computed property
+        ko.defineProperty(model, 'subtotal', () => {
+            return "$" + (this.price * this.quantity).toFixed(2);
+        });
+
+        // Accessing the observables
+        ko.getObservable(this, "price").subscribe(function (newPrice) {
+            console.log('The new price is ' + newPrice);
+        });
+    }
+
+    public getSubtotal(): string {
+        return "$" + (this.price * this.quantity).toFixed(2);
+    }
+}
+
+class Order {
+    lines: Array<OrderLine> = [];
+
+    constructor() {
+        ko.track(this, ["lines"]);
+    }
+}
+
+var someOrderLine = new OrderLine(null, 0.445, 11), anOrder = new Order();
+
+someOrderLine.item = "Test Item";
+someOrderLine.quantity += 1;
+
+anOrder.lines.push(someOrderLine);
+anOrder.lines.push(someOrderLine);
+anOrder.lines.shift();
+
+console.log(someOrderLine.subtotal == someOrderLine.getSubtotal());     // true
+console.log(anOrder.lines.length);                                      // 1
diff --git a/knockout.es5/knockout.es5.d.ts b/knockout.es5/knockout.es5.d.ts
new file mode 100644
index 000000000..ffd1cffa0
--- /dev/null
+++ b/knockout.es5/knockout.es5.d.ts
@@ -0,0 +1,14 @@
+// Type definitions for Knockout-ES5
+// Project: https://github.com/SteveSanderson/knockout-es5
+// Definitions by: Sebastián Galiano <https://github.com/sgaliano/>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+/// <reference path="../knockout/knockout.d.ts" />
+
+interface KnockoutStatic {
+    track(obj: any, propertyNames?: Array<string>): any;
+    defineProperty(obj: any, propertyName: string, evaluator: Function): any;
+    defineProperty(obj: any, propertyName: string, options: { get: () => any; set?: (value: any) => void; }): any;
+    getObservable(obj: any, propertyName: string): KnockoutObservable;
+    valueHasMutated(obj: any, propertyName: string): void;
+}
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