About the Author

William Gurstelle is the author of "Adventures from the Technology Underground," "Backyard Ballistics," "Building Bots," and "The Art of the Catapult." The number of hours he s spent crafting fighting robots and catapults instead of working at, say, his normal job (as an engineer) is, in Bill s own words scary to contemplate, but it serves a purpose. When not building devices that make stuff go whoosh, boom, and splat, Bill is a contributing editor at "Make" magazine and writes frequently for "Wired," "The Rake," and several other national magazines. He lives in Minneapolis."