·Unprecedented access behind Half-Life and Half-Life 2 ·A forward by Valve founder Gabe Newell ·Hundreds of art, design, preproduction, and other art pieces crammed into the book ·Over a dozen key members of Valve"s staff interviewed ·Officially approved by Valve ·Behind City 17 and other locations ·The development of the Source engine ·A rogue"s gallery of beasts, characters, and monstrosities ·Key weapons development revelations ·A tour of many of the game"s locations, from inception to completion ·Filled with art, screens, and anecdotes from the Valve team