Bugs are a fact of programming life, although their consequences have changed a lot. When a console crashes, you reset it. When an arcade game crashes, it resets itself. When your PC crashes, you might have lost an important document. If you're going to have a bug, best to experience it in a game and not Microsoft Word.
Everyone knows video games have bugs these days. Not as many people know they've always had bugs, going right back to the beginning. Pac-Man, Galaga, Defender, they had more bugs than you'd suspect, and sometimes they laid right under your nose, unnoticed for decades, until you find out how to trigger them.
That's what this book is, a spotter's guide to classic game bugs: where they are, how to find them, and how to push them out into the open, so we can pin them to cardboard and put them on display. What use is a bug to anyone if it's crawling in the walls? Let's bring out the magnifying glass and have a good look. The wing pattern on this Pac-Man kill screen is really quite exquisite.