The author wanted a very distinctive cover that conveyed both the hand-made aspect of programming, and the idea of “classes” of objects. I translated this into classes of insects—or bugs—so the design alluded to several levels of programming at once. The cover was inspired by the Arts & Crafts movement and it’s careful joinery.
This was the first edition. The second, third and fourth editions, which follow, use the same basic format, but with different backgrounds and types of wood. See the next edition.