"A clear pattern emerges... he latches on to some perceived fundamental weakness or contradiction in existing physical theory and worries over it for long periods of time—as long as it takes. He is concerned not to exploit existing ideas but to transcend them. This restless style is not necessarily a recipe for success. Einstein did not play a creative role in the development of physics after 1925... The basic difficulty was that Einstein believed he saw difficulties in the basic foundations of quantum theory and that, characteristically, he wished to overhaul the theory rather than to exploit it. While his colleagues were applying quantum theory with great success to elucidate the workings of atoms, nuclei, and bulk matter, Einstein held aloof."