For more than 70 years, Pablo Picasso kept his ideas and thoughts in a series of sketchbooks; by 1964 there were 175 volumes, forming a startlingly close-up visual record of his mind at work. Six scholars explore a half dozen of these volumes in depth here, tracing how masterworks like The Saltimbanques, The Demoiselles, and The Sabines took shape. Two reminiscences, from the artist's long-time love Françoise Gilot and their son Claude Picasso, provide a more personal understanding of the importance of these sketchbooks to the artist.