Many years ago, I read the book Moe Berg: Athlete, Scholar, Spy. It went into great detail about Berg's intelligence work. That book was published in 1976; there's a later biography available as well.
Most interesting to me was a story which shows just how far we were prepared to go to prevent Nazi Germany from obtaining nuclear weapons. Berg was sent to Zurich, Switzerland to attend a lecture by Werner Heisenberg, noted German nuclear physicist and the head of Germany's efforts to develop nuclear arms. Berg's orders were simple: If after hearing Heisenberg speak, if Berg had any certainty that Germany was close to developing nuclear weapons, he was to kill Heisenberg. Berg determined that the Nazis were nowhere near having these weapons, so Heisenberg was spared; postwar investigation in fact determined that the Germans were in fact nowhere near developing the atom as a weapon.
about Moe Berg multi-talented baseball player. He had degrees in Romance languages from Princeton and the Sorbonne, a law degree from Harvard, and was a spy for the US from 1930 to 1941 and then a translator and intelligence person through the war. I mentioned that to a friend of mine who is a baseball junkie only to be presented with a copy of his biography. What a guy. Fluent in 12 or more languages. Picked up Japanese during a month long tour of Japan with Babe Ruth and various other major leaguers to the point that he was able to correct native Japanese speakers grammar. He appears to have been incredibly well liked by everyone he came in contact with, and an episode of the radio program Information Please was set up to stump him with 7 very difficult questions. Berg got them all.
The book makes him seem like someone I'd love to have known.