Among the major activities of the Director of the Old Spanish Trail Association was to compile lists: of members, of towns and counties and their contributions, of councilors and their duties.

This "Membership Book" is a collection of columns of figures that kept the Director apprised of all these things. It is separate from the financial records maintained to show development of the highway itself. But the members listed here were important in raising funds to build the highway and often served as "Ambassadors" for the OST.

Also included in the Membership Books are lists of advertisers for publications produced by the Old Spanish Trail Association. Pamphlets, like "The Story of the Old Spanish Trail [pictured above]," intended for motorcade travelers, always paid for themselves via advertising dollars.