Mr. Knowles intended to document and provide "sketches of Former Industries & Other Enterprises of Crosswicks." At the beginning of Album 39 he provided a checklist of businesses from which to collect documentation, and a list of "Forgotten Industries." Both Album 39 and 40 contain invoices, letterheads, and other documentation of businesspeople and organizations that operated in Chesterfield Township, or provided services to people in the township between the late 19th century and the late 20th century. The bulk of material dates from the 1910s to the 1940s. It is arranged in alphabetical order; businesses based on an individual's name are sorted by the surname. The arrangement is largely as he left it, with some corrections to the order and some additional businesses.