A fond look at the life and career of the mathematician-turned-satirical-songwriter-turned-mathematician of whom The New York Times wrote, “Mr. Lehrer’s muse [is] not fettered by such inhibiting factors as taste.” He’s released no new songs in more than 40 years; as he said in 2002, “Things I once thought were funny are scary now. I often feel like a resident of Pompeii who has been asked for some humorous comments on lava.”