Hocus-Focus #2, by Hal Kaufman and Bob Schroeter ISBN 0451115279
Five out of stars
This is a book that will challenge your abilities to spot differences between two images, which sharpens the mind. There are 100 puzzles, each of which is composed of two captions on the same page. The goal is to spot at least six ways in which the two images differ. Some of the differences are fairly easy to spot, but others can take some time to identify. The answers are listed at the bottom of the page in inverted small print.
As long as the reader can see well, the puzzles can be solved by people from elementary school through the retirement years. It has been well documented that people that keep mentally active are better able to avoid mental decline in their later years. Therefore, one can convincingly argue that this book has medicinal value.