On April 21921, Jacob stood among the throngs at Battery Parkto greet the steamship Rotterdam which brought his idol, Einstein, to America for the first time. As he waited, he thought about the theory of relativity - a set of esoteric ideas that had madea scientist into an international celebrity.

Once Einstein headed off on his motorcade andthe crowds began to disperse, Jacob too, headed back.

At last I began winding my way home, taking care to avoid the main streets on the Lower East Side. I...