Pablo Picasso's widely reported lifestyle, his wealth and womanizing, and his meticulously documented method of working are legendary; his face has become a mythic symbol of the artist for millions around the world. Likewise, his immediately recognizable paintings, readymades, sculptures, and ceramics virtually stand for modern art. Reproductions of Picasso and his works decorate everything from college dormitory walls to neck ties, coffee cups, flatware, and umbrellas. Protean, bold, a daring experimentalist, and technical master, Picasso stands as the indisputable genius of twentieth-century art.

The process that transforms artworks into commodities reaches its most dizzying heights in the case of Picasso. His paintings, etchings, pottery, sketches, indeed, anything he scribbled upon brought small fortunes even as he produced them. For those who could not afford the real thing, there existed an endless supply of reproductions and imitations long before museum bookshops began covering all...