Have a tricky castle you need to get into? Roman army pounding at the door? Learn how to build your very own backyard trebuchet with this handy instruction book! Whoosh! Splat! This book contains detailed, step-by-step instructions on how to build real, working catapults and other siege machines in your very own backyard. These are not toys--you'll need an enthusiastic catapult-loving grownup with lots of supplies and tools to help, but there's nothing quite so satisfying as a siege engine you've built yourself.  For more fun projects, check out William Gurstelle's other book, Backyard Ballistics (Chicago Review Press, 2001), which will show you how to build the Potato Cannon, the Cincinnati Fire Kite, the Tennis Ball Mortar, and other slightly more modern rockets and catapults. Have fun!