Linus Pauling showed evidence for a helix and planar base stacking along the helix axis. Early in 1953 Watson and Crick proposed a correct structure for the DNA double helix. Pauling later cited several reasons to explain how he had been misled about the structure of DNA, among them misleading density data and the lack of high quality X-ray diffraction photographs. During the time Pauling was researching the problem, Rosalind Franklin in England was creating the world's best images. They were key to Watson's and Crick's success. Pauling did not see them before devising his mistaken DNA structure, although his assistant Robert
Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid which subsequently turned out to be incorrect. Both Crick, and particularly Watson, thought that they were racing against Pauling to discover the structure of DNA. Max Delbrück was a physicist who recognized some of the biological implications of quantum physics. Delbruck's thinking about the physical basis of life stimulated Erwin Schrödinger to write, "What Is Life?" Schrödinger's book was an important influence on Crick and Watson. Delbruck's efforts to promote the "Phage Group" (exploring genetics by way of the viruses that infect bacteria) was important in the early development of molecular biology in general and the development of Watson's scientific