Two of the most interesting and pioneering British artists of the 20th century may be just as crucial in the trajectory of modern art for their private lives, their biographies, as for their painting. Vanessa Bell was a significant woman artist, for whom portraiture was a central preoccupation, and whose personal life, as a member of the Bloomsbury Group, has been the subject of endless study. Her complex life story has almost obscured her art, which...