After 50 years of creatived activity at the forefront of theoretical physics, Efim Fradkin died in Moscow on 25 May. His research extended from pioneering the functional method in quantum field theory and discovering, simultaneously with Schwinger, its Euclidean formulation, to basic work in string theory.

He was born in a Jewish neighbourhood near Minsk. At 16 he the university there for a year. The famous mathematician I M Gel'fand, who occasionally lectured there, recognized Fradkin's outstanding abilities and, to support him, gave him 100 roubles. However, the war intervened and Fradkin's family were killed. He joined the army and was wounded in the Battle of Stalingrad.

Fradkin appeared in Moscow in 1948 and was adopted by I E Tamm and V L Ginzburg at the Theoretical Department of the Lebedev Physics Institute, which became his home for the remaining 50 years of his scientific life.

"In the theatre of operations known as theoretical physics, Efim's attacks have been launched along the whole front", wrote Bryce DeWitt in Fradkin's festschrift. Fradkin pioneered conformal field theory and contributed to the theory of turbulent mixing. He developed the Batalin-Fradkin-Vilkovisky method for quantizing for general constrained systems, found new ways to solve spin lattice models, tackled the problem of grand unification via exceptional groups and studied transfer processes in plasma.

Fradkin introduced the method of Green's functions in relativistic statistics and discovered, alongside Landau and Pomeranchuk, the zero-charge behaviour of QED (better known in the West as the Landau pole). He discovered open algebras and invented the first example of gauge supergravity. His relativic eikonal approximation and the Efimov-Fradkin non-perturbative calculus gave birth to whole new trends of research.

Fradkin was awarded the Stalin state prize in 1953, the I.E.Tamm prize in 1980 and the Dirac medal in 1989 and was the first recipient of the Sakharov medal in 1996. He was a foreign member of Accademia Pontaniana in Naples and a full member of the Academy of Sciences of Russia. He was a member of CERN's Theory Division, as guest professor of the director-general, in 1996/7.

The rest fifty years of his life belonged to the Lebedev Physics Institute, Academy of Sciences, Moscow, except for a certain period in the early nineties, when he was toiling towards a creation of an International Centre of Advanced Study and Technology in Ann Arbor, Michigan, USA.

The Full Member of the Russian Academy of Sciences, Professor E.S.Fradkin was one of those few outstanding scholars, who have set trends of quantum theory of matter and field in the heroic time when this most profound knowledge of nature got its impetuous advancement.

In the fifties E.S.Fradkin developed the functional path integral formulation of QTP and obtained the completely renormalized set of Schwinger-Dyson equations and invented the thermal diagram calculus for quantum statistics. The Ward-Takakhashi-Fradkin-Slavnov identities are basic in the theory of gauge fields. In the sixties he discovered the modified perturbation expansion named after him, and the Fradkin-Efimov superpropagator method for serving non-linear interactions. E.S.Fradkin was a pioneer in formulating the theory of non-Abelian gauge fields, renormalizable theory of weak interactions. In the seventies he proposed the asymptotic freedom requirement as a criterion for selecting Grand Unification models, obtained the first gauged model of extended supergravity. In the eighties he proposed the effective action approach for fundamental fields in string theory, discovered infinite- dimensional higher-spin symmetry in the anti-deSitter space and proposed the corresponding supergravity model. In the nineties he introduced a conformal supergravity extension based on new infinite-dimensional conformal higher- spin gauge symmetry, proposed a gauge-invariant approach to geometric quantization. The canonical quantization method of systems with most general typies of constraints can be traced back to Fradkin's work of 1973. Later it turned to what is now known as a universal Batalin-Fradkin-Vilkovisky method that serves any imagionable gauge field or string theory, including those with curved phase space (1986 - 1990). Fradkin's favourite baby was the conformal field theory that he was elaborating since 1974 and up to his last days.

Such are some out of many other Fradkin's contributions which either suited the immediate needs of the current development of QFT or/and are to remain cornerstones of its future welfare and advancement.

E.S.Fradkin won the State Prize in 1953 (Stalin Prize of Second Degree), I.E.Tamm Prize of the Academy of Sciences in 1980, the Dirac Gold Medal of ICTP in 1989. He was elected a foreign member of Accademia Pontaniana (Naples, 1983) and awarded military and civil orders.