“If one loves old photographs, with all their compelling I magic, there is no happier a hunting ground than the I Prints and Photographs Division of the Library of Congress.” So writes Oliver Jensen, the former editor of this magazine, in the introduction to America’s Yesterdays , a unique collection of some of the library’s least-known pictorial treasures, which American Heritage will publish this fall.

The Library of Congress began acquiring pictures seriously in 1870, when it took over from the federal district courts the assignment of filing copyright deposits. (In order to copyright a picture, a photographer had to deposit two copies, their corners often marred with scribbled names and numbers.) The flow from that source dwindled after 1909, when a new law permitted photographs to be copyrighted along with the rest of the book or magazine in which they appeared, and by now copyright deposits account for barely 20 per cent of the collection. The rest includes purchases, private gifts, and pictures transferred from other arms of the government (such as the 272,000 negatives and 150,000 prints from the Farm Security Administration).

No one knows how many images there are in this national collection. In-house guesses—and they are only guesses—run anywhere from 8,000,000 to 15,000,000. The library’s hard-pressed professional staff has never been able to keep up with the incoming tide, and no more than 60 per cent of the collection has been even roughly catalogued.

The idea for Jensen’s book was born in the late 1950’s, when he was visiting the Prints and Photographs Division in search of unpublished pictures for A MERICAN H ERITAGE . The division’s late chief, Edgar Breitenbach, led him to the vast, hot attic of the main building where the bulk of the collection was then stored in boxes, trunks, and packing cases. Both he and Breitenbach realized, Jensen writes, that Congress was sure to be slow in appropriating funds with which to rescue and sort it all—since “old photographs left lying in attics do not have much of a voting constituency.”

Some twenty years and another book of rare photographs—the widely hailed American Album , published by American Heritage in 1968—intervened before Jensen could return to the task. Together, he and his skilled assistant, Shirley Green, pored over thousands upon thousands of pictures, most of them now stored in the air-conditioned sub-basement of the library’s Annex, for this new volume. As they sifted, they kept two goals in mind: to convey a sense of the extraordinary richness of the library’s untapped wealth, and to create a fresh portrait of the half-century between 1870 and 1920—the date past which, Jensen writes, “the photographic record becomes massive and modern in appearance, [and] in some undefinable way the unique flavor departs from the collections.”

From the 330 photographs—many of them never before published—that will appear in America’s Yesterdays , we have selected rare