One of the most influential people in maths was Fibonacci. Most people that have taken Pure mathematics, have studied the Fibonacci Sequence in detail. But who was Fibonacci? A book on Leonardo da Pisa, or Fibonacci as he has been known, will be published later this year.

This is a preview about the book, and a bit about the man himself:

http://www.npr.org/2011/07/16/137845241/fibonaccis-numbers-the-man-behind-the-math

The book is "The Man of Numbers" by Keith Devlin.

Any other biographies, sites or articles on well or lesser known people that influenced mathematics?