Puzzles in Math & Logic by Aaron J. Friedland (Dover, 1970) is a short volume, 66 pages in length, that contains 100 puzzles testing your mathematical and logical ability, and includes answers.

The author states in the introduction that he has attempted to make this book a collection of original puzzles. Several of them are puzzles that you won't find anywhere else, although, of course, 42 years hence, several others can now be found in various other collections.

There is good variety in the puzzles and include alphametics, chess puzzles, what one might nowadays refer to as lateral thinking puzzles, and other puzzles of a general mathematical nature. The puzzles fall into a few different themes. Some might be what might be called "trick" problems. Others can be resolved through direct calculation, but the result is quite counterintuitive. Others simply require lots and lots of calculation. Friedland refers to these two elements as "surprise" and "challenge" in the book's preface. In general, I would peg the difficulty level of the puzzles as being moderate to high, not so much because they involve advanced mathematical concepts, but because many of the puzzles are such that it's often difficult to find the correct approach for solving them.

The puzzles are generally of high quality. Of course, in any collection as large as this, it is possible to nitpick (e.g. Friedland ignores the possibility of multiple solutions for the alphametics, and for #88, which could be classified as a "lateral thinking puzzle", the solution conflicts with our real-world understanding of decision-making), but generally the puzzles are quite good.

One minor annoyance that's worth mentioning: The front cover gives away some of the solutions!

**Rating:** 9/10.