Form, material, color, space. These are the properties that were important to minimalists Dan Flavin, Donald Judd, John McCracken, and Fred Sandback. In this exhibition, the work of each artist has its own room. Judd was the oldest, born in 1928, and Sandback the youngest, born in 1943, but the four shared preoccupations with grids, planes, and permutations. A wonderful opportunity to compare and contrast these late masters. —E.C.