Linus Pauling returned to America in 1927 fired with the inspiration of the new quantum mechanics. He was one of the first Americans to understand the importance of the European revolution in physics, and one of the first to apply its lessons to the field of chemistry.

He returned to the school at which he had earned his doctorate. Caltech was booming when Pauling came back. Under physicist Robert Millikan’s aggressive leadership, the number of students had grown to six hundred by the fall of 1927, including one hundred graduate students. The Caltech physics department now published more papers per year than any group in the nation. Pauling’s mentor, the great chemist Arthur Amos Noyes, was making the chemistry division into a world leader. Astronomer George Ellery Hale was negotiating a stupendous grant to build the world’s biggest telescope atop Mount Wilson. A department of geology had been started, and an aeronautics laboratory was on the drawing board.

Most important, word had just been released that the nation’s most renowned geneticist, Thomas Hunt Morgan, was coming to start a biology division. Biology, along with physics and chemistry, would complete the triumvirate of sciences at Caltech, and Morgan, the man who had narrowed the site of the gene down to individual chromosomes–and in doing so made his experimental model, the fruit fly, famous–was the perfect leader. His arrival in 1928 immediately made Caltech a national force in biology.