William Gurstelle

Adventures from the Technology Underground

The Art of the Catapult

Whoosh Boom Splat

Ready the Cannons!

Defending Your Castle

Backyard Ballistics

Adventures from the Technology Underground: Catapults, Pulsejets, Rail Guns, Flamethrowers, Tesla Coils, Air Cannons, and the Garage Warriors Who Love Them (Unabridged)