Nearly all of the 20,000 poster designs made by the WPA have disappeared. This book provides a history of the period 1935 - 1943 when the Fine Arts Project of the WPA produced those posters. It includes brief memoirs by some of the artists, as well as by historians of the era.
What I enjoyed most about this book was the sheer optimism of many of the posters, produced at a time when there wasn't much to be optimistic about.