What you need for this book

You will need Steam, a high speed internet connection, and just some time. In order to get the most out of this book, you'll want to purchase a copy of one of Valve's Half-Life 2 games, as this book focuses on scripts and development for Half-Life 2: Episode Two. It's not necessary to purchase a game; however, you can create a mod for free with the Source SDK and create your own game from scratch.