In 2010 John Barnes published Gems of Geometry. The book was based on a series of lectures he had given on a variety of geometry topics that he finds fascinating. After fielding requests to do the same for numbers, Barnes agreed. He gave lectures on numbers and their properties at both Reading and Oxford. In 2016 those lectures were published under the title Nice Numbers.
The lectures comprise the ten chapters of the book. Some of the topics are very basic, and historically interesting, such as Measures, Time, and Notations. Other chapters discuss properties of primes and the RSA algorithm. In all cases Barnes presumes little to no background knowledge. He provides all of the necessary historical or mathematical information that allows the reader to understand his explanations. Thus, the book is suitable for any reader who can do high school level mathematics and has the interest and curiosity to follow Barnes on his wide-ranging explorations. Each chapter ends with suggestions for further reading; most chapters have some exercises for the reader to attempt, although no answers are provided. The more challenging exercises are marked with an asterisk.