In Gary Giddins’ Satchmo, the companion volume to a televised documentary first aired in 1988, Giddins credits New Orleans music historian Tad Jones thusly: “Tad, in true Lew Archer fashion, sussed out census reports and followed leads that led to the baptismal registry of the Sacred Heart of Jesus Church and certification of Louis Armstrong’s true birthdate (August 4, 1901).”

Until Tad Jones did his sleuthing, most writers accepted Louis Armstrong’s own oft-repeated assertion that he was ...