Molecular Biologist Daniel E. Koshland, Jr., was one of the most fascinating men I have ever had the pleasure to know. So, it was painful to read in this morning's Washington Post that he passed away on Monday, following a stroke, at the age of 87. Dan was a real polymath -- fascinated about every subject imaginable, and a genuine expert in many. He also happened to play a role in two of the 20th Century's most important scientific revolutions. In graduate school at the University of Chicago in the early 1940s, he worked on the Manhattan Project. After the War, first at Brookhaven National Laboratory and then at Cal Berkeley, his work focused on enzymology, laying foundations in that field that would become important to the field of recombinant DNA, or biotechnology. From 1985 to 1995, Dan was editor-in-chief of Science, one of the most important scientific journals in the world. Dan's first wife, the immunologist Marian Koshland, was a highly regarded scientist in her own right. Both of them were elected to the prestigious National Academy of Sciences -- one of the few, if not the only, married couples to be so honored. Another quite remarkable thing about Dan Koshland was his openness, congeniality, and modesty. Although he was a man of considerable means, who donated tens of millions of dollars to educational institutions, scientific research, and other causes, Dan was always most generous with his most valuable asset: his time. Into his late 80s, Dan continued to conduct research as well as supervise and mentor half a dozen graduate students. But even a schlub like me could pick up the phone and chat with Dan, or drop in on him when in the Bay area. He was a kind and intelligent man, and he will be missed.