At first, you might imagine that the title refers to the computer opponents in various twitch games like Doom or Quake. But no. Sawyer means the fanatic gamers, to whom he addresses the book. He being one himself.
Chapters span all the important topics of computer gaming. From personalising your hardware through overclocking the CPU to tips on searching eBay for items. Plus, of course, on the latter, you can sell various gaming memorabilia.
He also provides ancillary data on books and movies spawned from games. Though he thinks most of the movies are purely dross. There is a fascinating table of the books in Chapter 7. You may be surprised by how extensive it is, with several books being written by well known authors like Mercedes Lackey and Alan Dean Foster. (The money is good for such purely work-for-hire, I guess.)
Most importantly to some of you, he tells how to hook up to the competitive gaming scene, with lists of various regional conventions for the hard core. Interested?