The Pythagorean Theorem by Alfred S. Posamentier.  2010, ISBN 978-1-61614-181-3. Subtitled: The Story of Its Power and Beauty.
The cover shows a "Pythagorean Tree" constructed from layers of Pythagorean triangles with squares on their sides. (Discussed in chapter 7.) This book is similar to the book by Eli Maor, but covers topics not discussed in that other book. Both books are worth reading.
Purchased from amazon.com, 10-5-2010, for $19.71.