This puzzle collection is a great assortment of mathematical-logical thought cultivators. It presents novel puzzles interspersed with a handful of classics. These challenging brainteasers will set students on a path of deductive reasoning.
—Michael Davis, Mathematics Teacher, November 2012

This is a perfectly delightful book which will provide many hours of pleasure to the mathematically inclined child or adult. It would be a nice birthday present, for example.
—Norman R. Draper, International Statistical Review, 2012

Train Your Brain is an enjoyable way to exercise your brain and spend a few spare minutes during the day. While this collection of math and logic puzzles vary in depth and complexity, they are certainly challenging enough to keep anyone engaged. I found the structure of Grätzer’s book to be particularly appealing. … I really enjoyed solving and attempting to solve the puzzles presented in this book. … most could be solved by anyone from an advanced high school student to a college student with a solid background in mathematics. There is something for everyone in this book.
—Janet Shiver, MAA Reviews, February 2012