“If Moe Berg didn’t exist,” says one of the talking heads in Aviva Kempner’s new documentary, “you would have had to invent him.” Berg was a major-league catcher during the 20s and 30s, notably for the White Sox and the Washington Senators. He also spoke ten or 12 languages (there’s some dispute among Kempner’s sources, although it’s agreed he couldn’t hit in any of them), got a law degree from Columbia University in the off-season to please his immigrant father, displayed his prodigious knowledge on a wide range of subjects on the radio program Information Please, and, most interestingly, served in World War II as a field agent for the Office of Strategic Services, a forerunner of the CIA. Given that he was a spy, it’s perhaps unsurprising that Berg remained an enigma even to his family and teammates, but he remains an enigma here too. Strangely, very little of his voice or personality come through, despite what appears to be a wealth of letters, newspaper interviews, radio appearances, and an article he wrote for the Atlantic on the subject of pitchers and catchers that references ancient Greek philosophy. We may still have to invent him.