Harald Petrovich Keres (born 15.11.1912) is a Soviet theoretical physicist and an academician of the Academy of Sciences of the Estonian SSR (1961). He was born in Pärnu. He graduated from Tartu University (1936) and worked there (head of a department in 1949-58 and vice-rector in 1958-60), in 1950 —73 at the Institute of Physics and Astronomy of the Academy of Sciences of the Estonian SSR (in 1950 — 55 head of the astronomical observatory and in 1960 —73 head of a sector), and from 1973 he has been head of a sector at the Institute of Physics of the Academy of Sciences of the Estonian SSR.
His research was mainly in the field of the relativistic theory of the gravitational field and of general relativity (the nature of the principles of equivalence, general covariance and relativity, the problem of the inertial system in the theories of Newton and Einstein, the solution of practical problems). He developed a method for the limiting transition from Einstein's theory to Newton's theory. He found gravitational fields of a non-Newtonian type which can be interpreted as fields describing gravitational vortices.