Assessment According to Jeff Sonas' Chessmetrics rating system, Geller was ranked No. 2 in the world May–July 1963, and was in the world's top ten for much of the 1950s and 1960s. After FIDE adopted the Elo rating system in 1971, Geller appeared in the top 10 three times: in 1971 (equal 6th, 2630), 1976 (equal 8th, 2620) and 1981 (equal 10th, 2615). Geller had an overall plus score against four world champions: Mikhail Botvinnik +4−1=7, Vasily Smyslov +11−8=37, Tigran Petrosian +5−3=32, Bobby Fischer +5−3=2. In total, Geller played ten and beat eight world chess champions, and his overall record in games in classical chess against world champions is positive: +39−36=131 (Max Euwe +1−1, Mikhail Botvinnik +4−1=7, Vassily Smyslov +11−8=37, Mikhail Tal +6−6=23, Tigran Petrosian +5−3=32, Boris Spassky +6−10=22, Bobby Fischer +5−3=2, Anatoly Karpov +1−2=5, Garry Kasparov +0−1=2, Viswanathan Anand +0−1=1). Geller did rather badly against Korchnoi (+6−11=16) and Polugaevsky (+4−11=21). Lifetime scores against top grandmasters Note: only official tournament and match games in classical chess are counted here. Legacy Geller is best remembered today for the tactical ability and original attacking style which characterised the earlier part of his career. In later years he became a more rounded player. He was noted as an openings expert, and was one of the pioneers in developing the King's Indian Defence to prominence, along with fellow Ukrainians Isaac Boleslavsky and David Bronstein. Geller also greatly advanced the knowledge in several variations of the Sicilian Defence, such as the quiet line with 6.Be2 against the Najdorf Variation 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6, which he used to defeat Bobby Fischer. He introduced the sharp Geller Gambit (1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.e4) against the Slav Defence. He acted as second (assistant) to World Champion Boris Spassky in the World Championship match of 1972 against Bobby Fischer, and later seconded World Champion Anatoly Karpov, as well as his lifelong close friend Tigran Petrosian. His books included an autobiography, translated by Bernard Cafferty as Grandmaster Geller at the Chessboard (1969). This was later updated and reissued in 1983 under the title The Application of Chess Theory, and contains 100 well-annotated games. Former champion Botvinnik stated that, in his opinion, Geller was the best player in the world in the late 1960s. Geller seemed to be stronger in tournament play than in matches. Geller was featured in the 2014