Fairly sturdy for a paperback, this is indeed a varied collection. There are at least twelve distinct types of exercises it cycles through, although nothing this reviewer found particularly novel. The majority of puzzles are word-oriented, with a bit of math and spatial navigation thrown in. And the format is made up of simple black-and-white visuals.
While the subject matter is entirely appropriate for all ages, the skill requirements for most of these brain teasers sits at about the Middle-Grade level or higher. If you are looking for activities to pass the time (without resorting to screen time), The Train Your Brain Mind Exercise is certainly a viable option.