Series I. Genealogical Work includes the manuscripts and notes created by Perley Derby during his work as a genealogist. This series has been arranged into two subseries. Subseries A. Manuscripts include handwritten copies of family genealogies later published by Derby. There are three manuscripts in this subseries: "Descendants of William Hatch of Scituate, Mass"; "The Descendants of Nicholas Pickett of Marblehead"; and "Descendants of Jasper Blake, Hampton, New Hampshire". There are also photostats of the Jasper Blake manuscript in addition to Derby's handwritten manuscript. Subseries B. Notebooks and Notes include two sets of numbered genealogical notebooks, along with loose notes arranged by subject. The first group of notebooks, numbered from 1-14, was created by Derby early in his genealogical career. The notebooks include a vast range of genealogical resources including Essex County probate records, various church records, and inscriptions from tombstones and other cemetery records. The second group of numbered notebooks runs from 3-137. Although a majority of the notebooks are undated, it is estimated that these notebooks were created later in Derby's genealogical career. Many of these notebooks have a panel of names affixed to the front of the notebook or an index to help readers locate the family name of interest. These notebooks contain more genealogical research conducted in the New Haven, Connecticut region. These later numbered notebooks are attributed to Perley Derby, but it is unclear, given the handwriting and estimated date of creation, whether this is true. In many of these later notebooks, Louise Tracey of New Haven, Connecticut, a genealogist who also worked with the Gorham family, claims ownership of the notebook. It is unclear whether or not Tracey and Derby worked together during Derby's lifetime or whether Tracey was transcribing older notebooks of Derby's genealogical work. Both sets of notebooks have been arranged numerically. Other sets of notes created by Derby while working on family genealogies are arranged chronologically.