This document provides an overview of Google Web Toolkit (GWT), including its history and development, why it is still useful despite newer JavaScript frameworks, how it works, and examples of its use. Key points include: GWT started at Google but is now an open source project overseen by a committee including Google; it allows developing complex browser apps in Java that compile to optimized JavaScript; it enables strong typing and code reuse across platforms; major companies like Google use it for applications; and frameworks like Errai extend it for full-stack web development.