The following article is based on unpublished work of the late mathematician David Ross Richman (1956-1991).

David was a problem solver by temperament, with strong interests in number theory, algebra, invariant theory, and combinatorics. He did his undergraduate work at Harvard and received his Ph.D. in mathematics from the University of California at Berkeley, under the supervision of Elwyn Berlekamp. I met him at one of the annual convocations of the West Coast Number Theory Conference held at the Asilomar Conference Center in Monterey, California. His quick mind and unassuming manner made him a pleasant person to discuss mathematics with, and he was one of the people I most looked forward to seeing at subsequent conferences.

In one of our conversations in the mid-1980's, he mentioned his idea of playing combinatorial games under a protocol in which players bid for the right to make the next move. Over the course of the next few years, I urged him to write up this work, but he was too busy with other mathematical projects.

By the beginning of 1991, he had received tenure at the University of South Carolina, and was commencing his first sabbatical. He planned to spend the first half of 1991 in Taiwan and the second half at MSRI. He died on February 1, 1991, in a widely-reported accident at Los Angeles Airport in which many other people were killed. He left behind a wife, the mathematician Shu-Mei Richman; a daughter, Miriam; and his parents, Alex and Shifra.