Series I contains printed materials related to this book, published in 1926 by the New York Historical Society. The book is a compilation of the illustrations made by Lefferts of the uniforms of the American, British, French, and German armies during the American Revolution accompanied by his descriptions of the uniforms and the units that wore them. Included in Series I is the prospectus for the book, also published in 1926, which announces the plan for the publication with the title Uniforms of the American, British, French and Hessian Armies in the War of the American Revolution, 1775-1783. The prospectus describes the historical value of Lefferts' work and the remarkable extent of his research. As an example of the content of the proposed volume, an illustration and description of New York Artillery Company, Captain John Lamb, 1775, is provided. Also provided is a list of the uniforms that would be covered in the book. The prospectus states that the volume would be produced if a sufficient number of subscriptions were sold at the cost of $25.00 each. Series I also includes illustration plates printed for the book, which were perhaps proofs or extras, that have been mounted on cardstock with printed captions. This series also contains unbound signatures from the book that similarly appear to be extra copies. Neither the plates nor the unbound signatures form a complete set although there are many duplicates of particular items in each group.

Series II contains photographic copies of paintings made by Charles Lefferts from 1916-1921 for Rodman Wanamaker, the president of Wanamaker's department store on Broadway in New York City. Wanamaker commissioned a total of fifty-three watercolor and oil painting illustrations from Lefferts to be used for window display and public exhibition throughout the store. At the time of the closing of Wanamaker's in 1954, twenty-eight of the drawings remained in possession of the store. The paintings were photographed by the New-York Historical Society in 1955. The paintings were later sent to other Wanamaker stores in Westchester County, NY, and Philadelphia. The majority of the drawings depict scenes from the American Revolution although several show scenes from World War I. Each of the images is accompanied by a descriptive caption written by Lefferts. These illustrations are mentioned in the introduction of Uniforms of the Armies in the War of the American Revolution, 1775-1783 .

Series III includes printed illustrations, dated 1880-1923, which were collected by Lefferts. Illustrations are arranged alphabetically by country. The majority of the images have been mounted on cardboard. The material includes several sets of illustrations including French and German sets that provide information the country, regiment, and date of the uniform in those languages. There is also material from a variety of other sources. These include clippings, postcard, magazine art, and one group of four albumen photographs that are studio portraits of German officers.

Series IV contains duplicates of materials found in Series I.

This series includes documents found on the shelf in December 2021 that had not previously been recorded as part of the Lefferts collection. These were added to the finding aid at that time. The documents include Lefferts's research notes, some correspondence, sketches and other images of military uniforms, and books and other print matter. Generally, the books are either illustrated, with images of military garb, or military instructional texts.