Series I dates from 1946 through 1956 and includes 733 3 x 4 inch or smaller gelatin silver photographic prints and 35mm contact prints dry-mounted in groups on briefly captioned boards. Some of the boards have punched holes and may have originally been arranged in albums; most of these mounts have been dated with a stamp on the front and bear stamps on the verso with Robert M. Lester's name and mailing address in Chapel Hill, North Carolina. Photographs are arranged by date.

A large number of photographs of the United Nations Headquarters complex, under construction between East 42nd and East 48th Streets along the east side of First Avenue during the period of Lester's photographs, is depicted at various stages of development between 1947 and 1953, from initial excavation to the final dominating tower of the Secretariat building. Lester used a variety of vantage points to capture the construction, including several rooftop views. Other construction photographs focus on the building of the Carnegie Endowment for International Peace building in 1952.

The East and Hudson rivers, including large ships, small boats, and the Brooklyn, Queensboro, and George Washington Bridges were captured by Lester's camera. Photographs along the Hudson River in upstate New York are also included.

Photographs from December 1947 depict the snow-covered cityscape of New York in the aftermath of a major blizzard. Other New York street scenes focus on the theaters, marquees, and signs of Broadway and Times Square.

Greenwich Village art shows, including the Sculptors Guild Exhibition in the spring of 1948, are detailed in a series of photographs, many of which show lively crowds gathered in Washington Square Park.

Included in this series are a few aerial photographs, such as those of Coney Island and Ebbet's Field taken from an airplane in 1950; also included are views of Idlewild (now John F. Kennedy International) and LaGuardia airports. One self-portrait of Robert M. Lester is available in a folder of undated photographs at the end of the series.

Series II consists of 244 35mm color slides, the majority of which are filed in vintage Filmdex slide files which are gathered into subject-based string-bound albums. Each album has an informal title page which has been briefly captioned in Lester's hand; albums are arranged alphabetically by title. One folder of Lester's loose slides of New York street scenes, signs, and theaters, is available at the end of the series.

"Art Shows" includes views of Greenwich Village art shows, mostly in Washington Square Park. The color slides show portrait artists at work, side-walk painting displays, and guitar toting musicians gathered with singers in the park. "Big Snow" depicts the city streets after the blizzard of December 1947. "Parks, etc." includes views of sun-drenched flowers, landscapes, ponds and birds in Central Park, The Bronx, and Fort Tryon Park near the Cloisters. Included are a series of photographs of children and adults launching large toy sailboats in Central Park. "United Nations Area" includes views showing the developing United Nations Headquarters site during and after construction between 1947 and 1954. "Waterfront" includes views of the Hudson River, the East River, the Queensboro and Brooklyn Bridges, the Midtown Skyport, seaplanes, tugs, ships, and docks. "Various" consists primarily of New York City street scenes, including views of shop windows, street construction, flowers, brownstones, and Washington Arch.