My 9 year old nephew just started learning to make maps with Forge and I loaned him my copy of From Gamer to Game Designer: The Official Far Cry 2 Map Editing Guide and thought I would mention it here. Although it was written for Far Cry 2, only the first 70 pages deal with the Far Cry 2 map editor - the other 230 cover game theory and FPS multiplayer level design and carries over very well to Halo. Amazon.com: From Gamer to Game Designer: The Official Far Cry 2 Map Editing Guide (9781584506867): David Hutchison: Books Subjects include general game design theory, military science, environmental geography, urban planning, designing to encourage different styles of play, etc. Although I had done level design before (Rogue Spear: Raven Shield and a brief stint as a level designer at a San Antonio based developer that went under) I picked up a few things from it.