While most art collectors were focused on consensus and the inside track, William Arnett looked outside the box—at “outsider” artists of the black American South. Vibrant assemblages and quirky sculptures, as well as women’s quilts, are a southern vernacular, and Arnett built a world-class collection of these striking works. Marlborough presents a selection of 75 pieces that tell stories of power and beauty, including works by Lonnie Holley, Hawkins Bolden, and Joe Minter. —E.C.