Most of the photos on this site were extracted from reference images (high-resolution tiffs, 20 to 200 megabytes in size) from the Library of Congress research archive. (To query the database click here.) Many were digitized by LOC contractors using a Sinar studio back. They are adjusted by your webmaster for contrast and color in Photoshop before being downsized and turned into the jpegs you see here.
Vintage photos of:

"City rowhouses, 1923." A jumble of humble abodes. The latest installment in our survey of backstreet Washington, D.C., this glass plate is another angle on the alley last seen here. Harris & Ewing Collection. View full size.
UPDATE: Shorpy member Mark H. has identified the location as Blagden Alley. The view is looking north toward the Henrietta Apartments on N Street; somewhere at left is the recent home of Back Alley Waffles.

March 1942. Washington, D.C. "Dancing class at an elementary school." Photo by Marjory Collins for the Office of War Information. View full size.

March 1943. "Kiowa (vicinity), Kansas. Train waiting for a block signal along the Atchison, Topeka & Santa Fe Railroad." Photo by Jack Delano. View full size.

October 1938. "Young farmer of Jefferson County, Kansas." One-hundred percent organic. Medium-format negative by John Vachon. View full size.

Circa 1907. "Kaatskill House, Lake George, New York." A place that separates the gliders from the rockers. 8x10 inch glass negative. View full size.

October 23, 1959. "Bloomingdale's, Hackensack, New Jersey. Green Room, Sutton Place. Raymond Loewy, client." Where all those Stepford Wives got their start. Large-format acetate negative by Samuel H. Gottscho. View full size.

Washington, D.C., 1925. "Justice Department, Nat'l. Bureau of Identification." Filing fingerprints at the forerunner of today's FBI. View full size.