Photo: courtesy AIP, Emilio Segrè Archives

Some years after Einstein published the General Theory of Relativity in 1916, he began to formulate an even more ambitious theory. Professional positions, first in Berlin and later in Princeton, gave him the latitude to work at his own pace. And after his wife Elsa died in 1936, Einstein's life increasingly centered on his work.

Einstein was driven by a vision. His goal was to describe all physical phenomena—from the smallest subatomic particles to the entire universe—under the umbrella of a "Grand Unified Theory." He never succeeded. But Einstein's dream did not die with him; the quest for the Grand Unified Theory is one of the hottest topics pursued in physics today. Einstein's work laid the foundation for much of the research into the evolution of the universe as well as modern technology, including lasers and computer chips. His enduring legacy will continue to inspire generations of great thinkers.