As the title says, this book is the recollection of fifty short articles written by the author. Most of them have appeared in publications for the general public.

These articles are related to the most varied issues, such as (just to give a sample selection) how many coins are needed in average for returning change, the blog of Terence Tao and his question about the best use of walkways in airports, a discussion of the Benford's law on the first digit of lists of numbers, the optimal number of moves to solve Rubik cube, the difficulties to create sudokus, the fact that checkers played by perfect players ends up always in a draw, the vote system to elect a new Pope, lives of mathematicians as Ramanujam or Gauss, and even several cases of flawed published results in prestigious research journals which have not been withdrawn and how editors and authors have behaved. Everything is written in an informal style, including anecdotes and avoiding any technical terms.

We point out explicitly two remarkable articles, which have been reprinted from the Notices of the AMS: an interesting interview to Stephen Smale, and the beautiful story of Bella Abramovna Subbotovskaya, who managed to help jewish people to learn high level mathematics under the Soviet system, losing her live because of this.

The book is not of high mathematical level, so it may let down a professional mathematician. As it is said in the back cover page, it makes nice airplane reading for someone interested in mathematics. It may be good as a present for those of our non-mathematician friends.