I had the pleasure of seeing Don Knuth present the "Nikoli Puzzle Favors" that is in this book. Nikoli is a leading publisher of japanese-style logic puzzles, which tend to have no words, such as sudoku, slitherlink, or number link. In Slitherlink, you must find a closed loop in a grid, so that for any numbers in the grid, the loop touches the number that many times.
Knuth implemented a solving method, and then investigated having more than one loop. He calls this variation Skimperlink.
One paper in here on leaper tours (like a knight tour in chess) affected my college work. I was working on a thesis for leaper tours, when Knuth published his paper, going far beyond anything I'd planned. I had to change my thesis.
Word cubes, magic squares, chess variants, and many types of puzzle fill out 49 chapters. One huge chapter on the 1977 computer game Adventure (pages 235-394) is perhaps excessive.
He writes about one of his first forays into algorithms, as an 8th grader, trying to make the most words out of "Ziegler's Giant Bar" in a 1951 TV contest. He told his parents he had a stomach ache and worked on the problem, gradually figuring out better ways to solve it. He won the contest with 4766 words.
This is a very fun book.