“You can draw a straight line between Art Nouveau and psychedelic rock posters,” Martin Hohn, president of the Rock Poster Society, says. “Mucha, Jules Chéret, Aubrey Beardsley. Borrow from everything ...

The assignment fell to Czech artist Alphonse Mucha (1860–1939), and it not only jump-started his career and a six-year partnership between the two—it helped establish him as one of the leading ...