Book excerpt: "This book results from research which was begun with all the casualness, but inherent seriousness, of the nineteenth-century amateur. I had the privilege of frequent access to the archives of the International Museum of Photography at George Eastman House and began to go through the nineteenth-century photographs in a systematic way. I wanted to go beyond the clichés of the history of photography as a series of often-reproduced masterworks and to find out something about the history of seeing, or at least of thinking about, images in the nineteenth century."--Préface.