From the Amazon description:
Instructions are clear, with full materials lists, helpful diagrams, and no skipped steps. Saw and drill are often required, along with hardware store purchases such as PVC pipe or specifically sized wood. Some of the finished results are large, such as God's Stone Thrower, a 5' x 5' construction with considerable flinging power, while a couple are smaller, tabletop-sized models that still propel successfully.
Here's where you can check out (and see some sample pages of) The Art of the Catapult: Build Greek Ballistae, Roman Onagers, English Trebuchets, and More Ancient Artillery