The Caroline B. Thomas Collection spans her entire career at Johns Hopkins. Included are materials related to the Precursors Study and to women's groups at Johns Hopkins, as well as manuscripts, personal papers, patient records, and other items. The Precursors Study materials include correspondence, grant applications, administrative records, and budget accounts. There are also records of her investigations into the use of sulfonamide as a prophylaxis for rheumatic fever. Patient-related materials include records from the Adult Cardiac Clinic (1935-1940). Records of the Women's Medical Alumnae Association of the Johns Hopkins University School of Medicine include a survey of women graduates of the school of medicine. There are early records of the Women's Advisory Committee and material pertaining to the Mary Elizabeth Garrett Room and to The Mary Elizabeth Garrett Symposium: Women Physicians in Contemporary Society, held at Johns Hopkins in 1979. In addition, the collection contains conference materials and documentation of Thomas's work with the Council on High Blood Pressure Research of the American Heart Association. There are also two volumes of transcribed letters exchanged between Thomas and her husband, Dr. Henry M. Thomas, Jr., while he served overseas during World War II, as well as papers relating to Thomas' honors and awards.