Negatives, approximately 1910-1921, depict buildings and street scenes in New York City, as well as views in Meadville (Pennsylvania) and Crawford County (Pennsylvania). Groups of photographs were taken for the New York and Washington real estate auctioneer Joseph P. Day. Also present are Hassler family photographs. There is also one box of photographic prints that were selectively made from glass plate negatives by the New-York Historical Society. ; William Davis Hassler (1877-1921) was born in Cochranton and raised in Meadville, Pennsylvania. He moved to New York City with his wife in 1905. There he worked first in business management before embarking in 1909 on a career as a commercial photographer that lasted until his early death in 1921. Hassler shot a wide range of subjects for a variety of clients, from magazines to construction companies, postal card publishers, and private commissions. Regular work came from the real estate auction house Joseph P. Day, for whom Hassler documented properties all over the five boroughs of New York City as well as Westchester County, Long Island, and New Jersey; and from the United Electric Light & Power Company, who he provided with images of power plants, illuminated signs, and product shots of electrical appliances of all kinds. Hassler was also an avid photographer of his family and friends, including his sister Harriet E. Hassler, who was head of the children's department of the Queens Borough Public Library, his wife Ethel Magaw Hassler, and his son William Gray Hassler. Hassler resided at 150 Vermilyea Avenue, apartment 44, in Inwood.