Everybody knows Tahl, but his opponent in this game is largely unknown. Dieter Keller (born 19 July 1936) is a Swiss chess master who was Swiss Champion in 1958, 1960, 1961, and 1963. He played for Switzerland in three Olympiads with modest results (+9 -9 =17). He was awarded the International Master title in 1961 and his last FIDE rating is 2359; he has been inactive since 2003.
Robert Huebner annotated it though. The first time his annotations were filled with errors and later Garry Kasparov copied Huebner's notes, mistakes and all. Huebner later corrected his notes; it took him 43 pages! I'm just giving the highlights here but the complications are incredible. Tahl finally wrapped things up with his amazing 29th move.