I own a copy of this book. It’s not very applicable to my day-to-day work, but it’s great fun to browse. I have used a few tricks from the second chapter which is available on the book’s companion site.
If you’re into this sort of thing, the Bit Twiddling Hacks page is also a great resource.
Funny you mention the Bit Twiddling Hacks – I recently started up a GitHub repo for bit twiddling hacks that’s in-progress until I gain enough motivation to finish writing it. I wanna aggregate Bit Twiddling Hacks, Hacker’s Delight, and a section out of the Programming in C book into a single reference source on GitHub. I have to think a bit more about how I’m gonna organize it though.