Hi Marg, You asked about: "The Ryerson Genealogy: Genealogy and History of the Knickerbocker Families of Ryerson, Ryerse, Ryerss; also Adriance and Martense Families; all descendants of Martin and Adriaen Reyersz (Reyerszen), of Amsterdam, Holland" By Albert Winslow Ryerson, Edited by Alfred L. Holman, Privately Printed for Edward L. Ryerson. Chicago (1916) It is available online at HeritageQuest, through your NYG&B membership. There are numerous Sarah Ryersons listed in the index, but no Bartow Underhill. However, you may want to access this book to see if any one of the Sarah's matches your criteria. Go to Books (HeritageQuest) and type "Ryerson Genealogy" in the Keywords field and it should come up on the first screen of hits. Best regards, Pam Sears