49-50<br> George Polya<br>Most famous for his classical problem book (known as Polya-Szego), he is also revered as the godfather of combinatorics.
L. J. Mordell and Gabor Szego<br>Speaking of Szego, here he is (right). Mordell was a great number theorist, known for, among other things, the deep conjecture (related to Fermat's last "theorem") that was proved by Falting (#579) in 1983.