For much of the 1940s, 50s, and 60s, photographer Harry Callahan's wife, Eleanor, was his most regular subject. She stares out of his acclaimed work, sometimes sharp and sometimes blurred, sometimes Classical and sometimes Modern, in public parks and city streets, at the beach, in a tent, in the studio and their home, nude and clothed, eventually pregnant and then mothering. The couple's longstanding collaboration makes up an intimate visual diary...