The development of medical librarianship during the last forty years is examined as reflected in the changes of its resources, technology, education, and knowledge base. A shift from historical to scientific inquiry constitutes the direction of medical librarianship. Its nexus is the gathering of information and the transfer of knowledge. The social and human resources for this ongoing change and the basis for a quest for excellence is seen in the pool of talent represented by hospital librarians and the aspirations of the women's movement for equality.