“Strewn throughout are competing symbols,” says Jim Shaw of his paintings, “including the mushroom cloud, the pillar, the egg, the alphabet, and the ocean.” These works—like Shaw’s practice of five decades—mine the strata of pop culture. In 2000, Shaw shocked London with a display of thrift-store paintings by American amateur artists, which one critic called “crapulous.” In 2013 in Paris, at the Chalet Society, he showed items from his collection of junk and memorabilia. Here at Gagosian Beverly Hills, the characters and motifs that populate Shaw’s portraits come from mythology, political history, and Hollywood. In a close-up portrait of Cary Grant, the image of Grant running in North by Northwest is imposed on the lower half of his face, but here he’s running from a hallucination. “I had been researching the history of psychedelics and power,” recalls Shaw, “which led me to Cary Grant (who was, before Timothy Leary, the most vocal proponent of acid), which led me to Esther Williams and her acid trip, which reminded me of her version of the romance with Jeff Chandler.” This is Shaw’s first show with Gagosian. —E.C.