He is the author of the book Blackjack Attack - Playing the Pros' Way, currently in its third edition, which is considered one of the most sophisticated theoretical and practical studies of the game ever written.
[1] In 2023 he and Dave Brolley coauthored, The Hi-Lo Card Counting System: A Complete Guide to Index Play.
Don began his professional life teaching mathematics and French in the New York City school system.
[2] Since his retirement from the finance industry, he has devoted even more time to blackjack, in a researching, writing, teaching, and playing capacity.
His contributions to the game include research into optimal betting, risk analysis, optimal back counting, Floating Advantage, camouflage and team play,[3]: 107, 122, 147, 227 He is most well known for: Schlesinger has edited, consulted and/or collaborated with many of the leading blackjack analysts, programmers, and authors, including Stanford Wong, Edward O. Thorp, Peter Griffin, Arnold Snyder, Karel Janeček, John Auston, Katarina Walker, and Norm Wattenberger.