Building on the founding discoveries and theories in the history of quantum mechanics, the first theoretical calculations in chemistry were those of Walter Heitler and Fritz London in 1927, using valence bond theory. The books that were influential in the early development of computational quantum chemistry include Linus Pauling and E. Bright Wilson's 1935 "Introduction to Quantum Mechanics – with Applications to Chemistry", Eyring, Walter and Kimball's 1944 "Quantum Chemistry", Heitler's 1945 "Elementary Wave Mechanics – with Applications to Quantum Chemistry", and later Coulson's 1952 textbook "Valence", each of which served as primary references for chemists in the decades to follow.