The papers of Dan Seymour span the years 1951 to 1974, although the bulk of the material dates from 1955 to the 1960s. They consist of correspondence, office files, memoranda, notes, client files and some advertisements, reports, charts, reprints, schedules, scripts, printed material, and calendars. The collection documents advertising history, especially television and the management of client accounts; the development of television shows and other aspects of television programming, including the selection of actors and audience profiles; advertising clients' account histories; the corporate administration of the J. Walter Thompson Company; and the career of Seymour. There is limited material about Seymour prior to his employment by the J. Walter Thompson Company in 1955 or after his retirement from it in 1974. Clients of the company represented in the collection include the Eastman Kodak Company, the Ford Motor Company, the Kraft Foods Company, the Lever Brothers Company, and the Liggett and Myers Tobacco Company. There is considerable overlap in the content of the series in this collection.

The work of the J. Walter Thompson Company Radio-Television Department, primarily in television, is chiefly documented in the Radio-Television Series. When he joined the company, Seymour's first objective was to reorganize its radio and television operations into a single Radio-Television Department because television had emerged as the leading media in the United States in the 1950s. The process of reorganization and overall administration of the Radio-Television Department is documented throughout the Radio-Television Department Series (Office Files and Thompson Company Offices). Aspects of administration documented include: the roles of company unit heads, such as the group heads or domestic office heads; relationships among the various units; operations of review boards; new business development; client relationships; and budgets. The New York office and other domestic offices, especially the Hollywood, Chicago, and Detroit offices, were key corporate links in television-related advertising. The New York office's radio and television activities are documented throughout Radio-Television Department Series; the Thompson Company Offices Subseries primarily documents the radio and television work of other domestic offices, but it includes a small amount of information about the New York office's operations. There is additional documentation for the Radio-Television Department in the Corporate Administration Series (Office Files).

Specific television programs and the scheduling of client advertising are documented in the Radio-Television Department Series (Programming), but radio programming is minimally represented. Availabilities and the Show Files are bound compilations of documents which provide information about programs available for J. Walter Thompson Company clients to sponsor. There are synopses of shows, which usually include descriptions of actors, directors, and producers, and scripts of various lengths. The Talent Showcase files appear to serve a similar function to those of the Availabilities and Show Files. More information on program availabilities for specific networks is in the Radio-Television Department Series (Networks). Screening reports, which are synopses of programs viewed by company staff, are scattered throughout the Availabilities and the Show Files binders, but the majority of the screening reports are found in the Radio-Television Department Series (Thompson Company Offices), especially for the Chicago, Hollywood, and New York offices. Some files for specific programs that were sponsored by company clients are in the Clients Series.

There is much overlap between the Corporate Administration Series and the Radio-Television Department Series in that both series contain information on the J. Walter Thompson Company's role in television advertising. The Radio-Television Department Series contains material on this topic from 1955, when Seymour was the director of this department, to 1967, during which time Seymour was also involved in company-wide management. The Corporate Administration Series also includes material related to the Radio-Television Department.

Not only does the collection document television advertising, it also pertains to Seymour's account management of J. Walter Thompson Company clients. In fact the Clients Series, which documents this activity, comprises almost one-half of the collection. This series particularly concerns advertising strategies, billings, the development of new business, and negotiations with clients. It also documents the conceptualization and production of television shows and motion pictures that were sponsored by individual clients. The call reports are records of telephone or personal contacts with clients and include information on many aspects of JWT-client relationships. Programs sponsored by the Eastman Kodak, Ford Motor, Kraft Food, Lever Brothers, and Liggett and Myers Tobacco companies are especially well described. Documentation for client accounts is also in the Review Board files of the Corporate Administration Series (Office Files) and scattered throughout the Radio-Television Department Series (Programming).

In addition to client activity, the collection reflects the corporate business of the company, especially as conducted through the New York office, in the Corporate Administration Series (Correspondence). In particular the Reading Files and the Norman H. Strouse correspondence pertain to this corporate activity. The series also includes general correspondence and topical files that are peripherally related to company operations. Strouse's letters concern corporate administration and management at the level of the President, and reflect the information exchanges and cooperation among the company's executive officers. The Strouse files span the period in which Seymour was elected to the Executive Committee and continue through his election to the Presidency of the company, succeeding Strouse. As Chairman of the Executive Committee, Seymour was responsible for all of the company's domestic operations. The Executive Committee files in the Corporate Administration Series (Office Files), include monthly reports for "New Projects" and include client names, the product or services involved, the nature of the project, and costs.

The Corporate Administration Series (Thompson Company Offices) also documents organizational issues in domestic offices other than the New York office. The establishment of the Chicago Office's review boards is documented in the subseries. The reports in the Corporate Administration Series (Reports), reflect research and concerns about internal J. Walter Thompson Company operations as well as client and public relations issues.

In the late 1930s through 1950, before Seymour joined the J. Walter Thompson Company, he developed relationships with radio and television celebrities, client-sponsors of programs, network and studio personnel, and advertising executives. These relationships continued in Seymour's work as an advertising executive in Young and Rubicam and the J. Walter Thompson Company. The congratulatory correspondence, mostly responses to Seymour's promotions, in the Radio-Television Series, the Corporate Administration Series, and the Miscellaneous Series documents these relationships. The invitations to professional and social events in the Corporate Administration Series (Correspondence) reflect the business of the corporate world beyond the J. Walter Thompson Company.