This collection of letters, diaries, and other types of documents (both original and copies) was assembled primarily by Mary Jane Peale, who copied, or had copied, many family documents. The bulk of the collection centers on Charles Willson Peale, James Burd Peale, and Mary Jane Peale.

The collection consists of diaries, 1890-1938, containing brief records of professional work and family events (49 vols.); also autobiography entitled "Memories for my boys," 1930 (B D713m), referring to his childhood and to his professional career and mentioning Franz Boas, William Comstock, Livingston Farrand, William W. Keen, S. Weir Mitchell, Elihu Root, and W. T. Sedgewick and also APS, University of Chicago, Johns Hopkins University, Yale University, and Wistar Institute (1 vol.); also a few miscellaneous papers, 1869-1932, chiefly letters to and from members of his family, and also Poultney Bigelow, Simon Henry Gage, and W. B. Van Ingen; two essays ("The Days of Man" and "A Venetian Night"): genealogical data; verses dedicated to his wife; extracts of letters to supplement his diaries.

Ernst Krackowizer (1821-1875), father-in-law to the anthropologist Franz Boas (APS 1903), was an Austrian born surgeon who fled Vienna to New York following his involvement as captain of the Academic Legion during the Revolution of 1848. Krackowizer was an active member of New York medical community, helping to found the German Dispensary and Hospital, later renamed Lenox Hill Hospital. During the Civil War, Krackowizer assisted the Union Army as a volunteer surgeon and inspector of military hospitals. Krackowizer is claimed to have been the first on whom the anesthetic effects of chloroform were tested in Vienna and the first to use a laryngoscope in the United States. This collection is comprised of the personal papers of Ernst Krackowizer including diplomas, certificates, correspondence, diaries, and photographs, which document his life and medical career. Krackowizer's experience in the Revolution of 1848 and subsequent flight from Vienna trough Germany to the United States is well detailed in his correspondence to his fiancée and later wife, Emilie Forster, and in his diaries, which make up a significant portion of this collection. Krackowizer firsthand description of the early use of chloroform and the laryngoscope are included, as well as materials documenting his involvement as a volunteer surgeon and hospital inspector during the Civil War. Additionally, the Krackowizer Papers contain material written by others reference the life and work of Ernst Krackowizer.

The manuscripts of father William Mitchell and daughter Maria Mitchell are not easily separated, and are treated here together. The collection includes William Mitchell's autobiography, his memoir of Judge Walter Folger of Nantucket, astronomical and meteorological observations, lectures, family and other correspondence.