The business series contains correspondence and other papers from Richards' various legal cases, dating 1913-1958. It includes correspondence concerning Columbia University and with Ernest L. Wilkinson.

Includes handwritten, typed, and shorthand diaries. Many are personal diaries from 1916 to 1961. Some of his diaries from the same time period are more business oriented. These include diaries about military service, ranches/farms/meat, cattle diseases, and several other subjects. Also includes his diary outlines and excerpts from his father's diary.

Includes notebooks and diaries of Clark's wife and children, including an autograph book with signatures of prominent figures. It also includes several items about theater and drama, including some play scripts.