Thames & Hudson Ltd Altering eye. photographs from the national gallery of art, hardback/sarah kennel

In 1949 Georgia O'Keeffe chose the National Gallery of Art as the custodian of nearly 1, 600 photographs by Alfred Stieglitz - the Key Set, as it has become known.

This book presents some of the most significant photographs acquired over the years, ranging from experimental photographs to key works by major twentieth-century figures.