This is a small Dover book, originally published in 1963. It is a survey of a broad range of topics in recreational mathematics, including ‘friendly numbers’, the Fibonacci sequence and its recurrence relationships and association with the Golden Ratio, magic squares (including some terrifically simple methods for generating magic squares), an excellent chapter on Diophantine problems and some standard solution methods, and much more.
I found my copy in a used bookstore in Victoria B.C. (the Russell Bookstore on Fort St. - well worth a stop), and I don’t know if the book is still in print. Not every chapter will appeal to every reader, but there is enough here to be interesting to anyone with an interest in mathematics.