The first 100 years of modern art witnessed the popularization of photography and an increasing emphasis on abstraction in painting, which threatened the survival of portraiture as a genre. It continued to flourish, however, because modern painters--Picasso foremost among them--sought and found new ways to portray the human face. The hundreds of works reproduced here illustrate the multiple solutions Picasso invented to solve the problem of the modernist portrait. Illustrations, 230 in color.