Hubble and Einsten are often credited, but the real heroes of the Big Bang revolution are the Russian Alexander Friedmann and Belgian priest Georges Lemaître. The Big Bang Revolutionaries amends the record, telling the remarkable story of how these two men, joined by the mischievous George Gamow and in the face of conventional scientific wisdom, offered a compelling view of a singular creation of the universe in what Lemaître termed a “primeval atom.”