- Prime Obsession: Bernhard Riemann and the Greatest Unsolved Problem in Mathematics
by John Derbyshire
http://www.olimu.com/Riemann/Riemann.htm
A nice combination of math and math history, similar to
Fermat's Last Theorem by Simon Singh.
I bought it a long time ago, finally got a chance to read it on the plane, marvelous book!
guanzhong