Linus Pauling was the most important chemist, and arguably the most important American scientist, of the twentieth century. From his descriptions of chemical bonds in quantum mechanical terms in the late 1920s and 1930s - a series of papers that culminated in the hugely influential book The Nature of the Chemical Bond - through his structural studies of complex inorganic and organic molecules and discovery of the chemical basis of sickle-cell anemia, Pauling's work leaped over the boundaries of disciplines and helped to revolutionize the study of chemistry.

In 1951 he was the head of the chemistry division at the California Institute of Technology, the acknowledged world master at solving complex molecular structures, author of hundreds of papers and several seminal textbooks, widely respected as a genius in his field, and a role model for Watson and Crick, who adopted the method he had used to attack proteins - a combination of model-building, chemical knowledge and modern physics - in their work on DNA.