My reasons for writing this book may very well contain a clue for its understanding and enjoyment. First, there are a great many beautiful and elegant facts and proofs in mathematics, which are published in widely varying places, if at all. I would like to shout about these problems froln the housetops, but have chosen the more dignified, and probably more efficacious, method of writing a book about them.

Second, many people consider mathematics to be a very boring, complicated subject. I hope to show that some facets of mathematics can be quite simple and interesting, although they are not obviously so at first glance.

Third, some of the most beautiful solutions of problems, of which I, alas, am not the originator, do not appear anywhere to the best of my knowledge.