Fonds contains notes taken by Thomas McCrae between 1897 and 1904 at William Osler's clinics at the Johns Hopkins Hospital, Baltimore.

The fonds contains original and typescript letters, manuscript notes, newspaper clippings, journal extracts, reminiscences and more, assembled by Harvey Cushing chiefly between 1920 and 1924 during the course of his research for the biography of William Osler. For the biography, Cushing collected and retyped over 7500 pieces of Osler's correspondence, among which are some original letters.

The fonds is separated into three series: Manuscripts, Working Notes and Osler's Correspondence. It also contains photographs, annual reports, publications, clippings, one watercolor painting, one postcard. Osler's correspondence is further arranged in three subseries based chronologically.

The fonds consists of books, letters, documents, drafts, publications, photographs, and several artifacts collected by W. W. Francis and Marian Francis Kelen over the course of their lifetimes. Many books and documents relate to Sir William Osler and the Osler family including several personal letters, the Deed of Trust documents regarding the Bibliotheca Osleriana, drafts of Osler's works, and a wooden travelling trunk that belonged to Edward Revere Osler. The fonds also includes original poetry written by Marian Osborne, W. W. Francis, and Marian Francis Kelen.