As the Medical Library Association prepares to enter its second century of service to society, it can look back with pride on the remarkable record of achievements of the association and its members, both personal and institutional, which are preserved for posterity in the Janet Doe Lectures. Established in 1966 by an anonymous donor, the Janet Doe Lectures on the history or philosophy of medical librarianship trace the development of health sciences libraries and librarianship and the evolution of the Medical Library Association. The major themes which emerge from this comprehensive review of the lectures published between 1967 and 1997 include the changing roles and values of health sciences libraries and librarianship; education and credentialing of health sciences librarians; MLA activities and concerns; and MLA/National Library of Medicine relations.