Alexei Zinovyevich Petrov (28.10.1910-9.05.1972) was a Soviet theoretical physicist and an academician of the Academy of Sciences of the Ukrainian SSR (1969). He was born in the village of Koshki (now Kuibyshev Region). He graduated from Kazan University (1937), where he worked in 1943-69 (professor from 1965). From 1970 he was head of a department of the Institute of Theoretical Physics of the Academy of Sciences of the Ukrainian SSR. His work concerned mathematical physics, general relativity, the theory of gravitation and philosophical questions of physics. He carried out a series of studies on invariant-group methods in the theory of gravitation. He developed new methods of studying gravitational radiation, the energy of the gravitational field and the modelling of gravitational fields, established the existence of three types of gravitational fields (the Petrov types), and classified gravitational fields by their groups of motion and by the conformal, affine and projective groups. He developed a general theory of the modelling of gravitational fields and put forward the idea of describing Einstein's theory of gravitation in terms of flat space. For the series of works “Invariant-Group Methods in the Theory of Gravitation” he was awarded the Lenin Prize in 1972.