This series contains items pertaining to Nowlan's attendance at Saint Saviour Elementary School, at Manual Training High School (now the Secondary School for Law, Journalism and Research) in the Park Slope neighborhood of Brooklyn, and at Brooklyn College located in the Midwood neighborhood of Brooklyn. Included in the series is Nowlan's certificate of diploma from Saint Saviour Elementary School, 1935, a report of his grades, and a corresponding commencement exercises program. The collection also contains two school yearbooks including a 1939 copy of Prospect, the Manual Training High School yearbook and Nowlan's Brooklyn College yearbook, Broeklandium, 1948. A commencement exercises program for Brooklyn College, dated 1948, is also included.

This series contains 122 color photographic prints, 165 color slides, and three black-and-white photographic prints, taken by Donald L. Nowlan, that document locations in Brooklyn in the 1960s and 1970s. Subjects include Coney Island, Brooklyn Botanic Garden, Prospect Park, and a Reenactment of the Battle of Brooklyn in Prospect Park (circa 1979).

This series consists of both color and black-and-white picture postcards of locations in Brooklyn such as Prospect Park, dating from circa 1875 to 1925. The postcards are presumed to have been collected by Nowlan.