The Stephen Henry Phillips papers document the life of this Salem, Massachusetts, attorney and his wife. The material consists of holograph essays, correspondence, notebooks, business papers, financial records, and legal documents. Phillips' personal papers provide some insights to his sentiments regarding slavery, the Hawaiian question, and American history. The professional papers document his legal and business activities after 1846. Included are the papers of his wife, Margaret, which consist mainly of correspondence, journals, and scrapbooks. Her papers shed some light upon the Phillips' home life in San Francisco through letters from her husband. The collection has been arranged in four series.

Series I. Personal Papers has been organized into five subseries. Subseries A. Writings includes a group of essays on topics in American history, particularly the question of Hawaiian sovreignity in the 1870s. Of particular interest are two essays on Hawaii that are bound with an introduction by Stephen Willard Phillips, his son. Other significant items are a centennial address to the citizens of Vallejo, California, and an essay entitled "Chinamen in America." Subseries B. Correspondence includes letters and letterbooks. Drafts of letters by Phillips to King Kamehameha V of Hawaii (1867) and Charles Francis Adams reveal his respect for the Hawaiian monarch and his admiration of Adams and other Harvard University graduates. The majority of the correspondence in this series concerns an article by Phillips on the role of United States Attorney General Edwin M. Stanton on the eve of the Civil War. Letters from George O. Holyoke and an enclosure in the Charles W. Clifford correspondence (November 17, 1892) provide personal recollections from the last days of the Buchanan presidency. Subseries C. Legal/Financial contains legal documents, stock transactions, promissory notes, receipts, account books and check books. Subseries D. Printed Matter includes certificates, news clippings, bulletins, annual reports, train tickets, invitations, and other printed items. Subseries E. Miscellaneous contains notes, accounts, receipts, a sketch, a blueprint, a handwritten family tree of the Appleton family, a blank books, and more.

Series II. Legal contains a collection of documents relative to murder trials, separation agreements, probate work, and corporate matters. Subseries A. Legal Practice contains records from his partnership with George P. Sanger and other law offices. Subseries B. Insurance Litigation/Legislation contains correspondence and records from Phillips' work at various insurance companies. Subseries C. Spaulding Partnership includes a register of cases handled in 1878 and 1879. Documentation of about 40% of the cases has survived. Each case is separated with a blank sheet of acid-free paper. Within each case, legal documents are filed first, then correspondence, followed by receipts and notes. A list of cases appearing in the register, but with no documentation, is listed in Appendix I. Of interest is an 1861 letter from Edwin M. Stanton to Phillips regarding Massachusetts vs. Rhode Island, a border dispute. Subseries E. Miscellaneous consists of cases that could not be associated with any particular Phillips office or partner. The cases are separated from each other by a blank sheet of acid-free paper. Within each case legal documents are filed first, followed by correspondence, receipts, and notes. Of interest is a deposition relative to litigation between Edward Muybridge and Leland Stanford concerning early experiments in motion photography.

Series III. Business Activities documents Phillips' close association with Charles Augustus Williams, who retained Phillips as his financial manager. Other papers illustrate Phillips' work as treasurer and trustee for mining companies in Southern California and Nevada.

Series IV. Margaret Duncan Phillips Papers contains documentation of her family life. Subseries A. Correspondence begins with letters from Margaret's arrival in Hawaii and describes her life there and in San Francisco. Later correspondence is associated with the journals that document Margaret's travels to Europe and the Far East in the early twentieth century. The letters to her sons, Stephen Willard and James Duncan, describe her visits to a number of European and Asian cities. Box 21 contains condolence letters to her son, James Duncan, and his wife upon Margaret's death in 1926. Subseries D. Photographs contains about 40 photographs of Spain, 10 photographs of Europe, 20 photographs of Hawaii, and about 50 postcards from various locations collected during her travels.