I am really enjoying this biography of Paul Dirac.
http://search.barnesandnoble.com/books/product.aspx?r=1&isbn=9780465019922&cm_mmc=Google%20Product%20Search-_-Q000000630-_-The%20Strangest%20Man-_-9780465019922
http://search.barnesandnoble.com/books/product.aspx?r=1&isbn=9780465019922&cm_mmc=Google%20Product%20Search-_-Q000000630-_-The%20Strangest%20Man-_-9780465019922