“Does anyone … still wear … a hat?,” asks Elaine Stritch in the Stephen Sondheim musical Company. She’s toasting the “ladies who lunch,” the last women to wear hats as the proper finishing touch to an ensemble. And then hats went the way of white gloves. This exhibition explores the role of headwear across American art, demonstrating the powerful symbolism of caps, straw boaters, felt cloches, and more. —C.J.F.