Reuben Fine (October 11, 1914 - March 26, 1993) was one of the best chess players in the world during the 1930s. He was also the author of several chess books which are still popular today. After World War II, he studied psychology, and wrote books on that topic as well.

Fine was born in New York City. He learned to play tournament level chess at the famous Marshall Chess Club in New York City, stomping grounds for many famous grandmasters like Bobby Fischer. Fine was considered one of the best, perhaps the best, players of blitz chess in the world. Fine won tournament after tournament - by 1937 he had won a string of international tournaments. In 1938, he tied for first place with Paul Keres in the prestigious AVRO tournament in the Netherlands.

In 1941 he wrote Basic Chess Endings, a compendium of endgame analysis which is considered one of the best works on the subject of its time. His The Ideas Behind the Chess Openings is also considered an important work for concentrating more on the underlying ideas of chess openings than on seqeunces of particular moves. During World War II he worked for the US Navy, performing the Pynchonesque task of calculating the probability of German U-boats surfacing at certain points in the water.

After the war, Fine continued playing chess, but began working on a doctorate in psychology, which he eventually received from the University of Southern California. In 1956 he wrote an article "Psychoanalytic Observations on Chess and Chess Masters" for a psychological journal. That article would later become the book The Psychology of the Chess Player. It is a fascinating subject, and Fine gives his insights into the topic, insights often steeped in Freudian dogma (Fine is not the first person to examine the mind as it relates to chess - Alfred Binet, the inventor of the IQ test, had studied the mental functionality of good chess players, and found that they often had enhanced mental traits, such as a good memory).

Fine continued playing chess throughout his life, but as time went on he began to focus more on psychology. Some wag noted that this was "a loss for chess, and at best a draw for psychology". Fine went on to publish A History of Psychoanalysis in 1979, as well as other books on psychology. One of Fine's more interesting beliefs was that homosexuality could be "cured, and his opinions regarding this were used in conjunction with legal battles in the US involving homosexuality, including the legislative battle over homosexual marriage in Hawaii.