“I had no real respect for good technique because I didn’t know what it was,” the photographer William Klein, who started off as an outsider in the art world, said in 2012. The American Folk Art Museum highlights the work of over 70 artists of the 20th and 21st centuries, all of whom remained self-taught for the entirety of their lives. The exhibition’s focus is in its title. The artworks are proposed to the viewer as “memory palaces”—creations that hold in suspension the pieces of imagery and information that add up to an individual. —J.V.