Books to pass the time Can you recommend an article/book about a curious subject.   I mean, not a textbook (well, or maybe), but something for reading to pass the time during the summer.
Thank you.
 A: Ian Stewart and Clifford Pickover have already been mentioned, both of whom have published many titles, Stewart's at a range of levels.
Roger Penrose has a number of reasonably accessible books on mathematical physics, cosmology, and related matters.
Paul Nahin's books cover a variety of topics; his In Pursuit of Zeta-3 is just out (I'm awaiting the arrival of my copy).
If you've any liking for matters of formal logic, you can find Raymond Smullyan's "puzzle books" which lead one gently and steadily more deeply into questions of logical reasoning, proof, even undecidability; start with What is the Name of This Book? and This Book Needs No Title.
I liked William Dunham's The Calculus Gallery, since the history of mathematics and of ideas generally is an interest of mine; he's also written on Euler's life work (on which he is a scholar).
Martin Gardner was not a mathematician per se, but had a considerable interest in the subject and met and corresponded with many of the living mathematicians of the second half of the previous century; while his books are generally filed under "recreational mathematics", he discussed a huge range of topics in his long-running "column" in Scientific American, which most of his books compile; his articles are easy (even entertaining) to read, but can lead into many deep issues (I learned about Smullyan from his writing).
If you have lots of time, there are Douglas Hofstadter's classic Gödel, Escher, Bach and Metamagical Themas (a compilation of his Scientific American column when he took over from Gardner; Ian Stewart also ran a column there for several years).
ADDENDUM:  I should also mention Avner Ash  and Robert Gross's books (not exactly a trilogy, but they cover connected topics)  Fearless Symmetry , Elliptic Tales (as in elliptic curves), and Summing It Up, should you want to know more about what number theory has been doing over the past 150 years or so.
A: The book The Math Book: From Pythagoras to the 57th Dimension, 250 Milestones in the History of Mathematics  is an excellent book written by Clifford A. Pickover. You will be surprised to see that how mathematics is inherent in our real life. This book is a blend of history and mathematics (essentially mathematical history) and I hope you will enjoy reading it.
