Another of my GURPS books made the jump to PDF from e23: GURPS Monsters can now be yours in instant download from: http://e23.sjgames.com/item.html?id=SJG30-6418
It just went “live” on April 25 and has been selling briskly, as far as my experience goes (which is not very far, admittedly). Enough so that in that handful of days, it pushed my royalties into the “cut a check” level all by itself, when otherwise orders for my previous books trickled in to get me a check every handful of quarters. So, good times, thank you, and go help out my May numbers if you don’t have yours yet!
Not convinced? There’s a 10-page preview available there as well, to try before you buy, and my designer’s notes are freely available on Pyramid. Or if you’d prefer the physical book, there are a limited number of those left too. (You can order it used or new from Amazon as well: GURPS Monsters; but today’s prices make that seem unlikely.)