This is one of those buildings with lots of marble floors, tall square columns, many hallways, many rooms (each with a number), and a real "old world" feel to it. The Irma and Paul Milstein Division of United States History, Local History and Genealogy is in Room 121 on the first floor. Here is the entrance to the Reading Room:
There is a microform room nearby, which has the copy card machine (buy one, and load it up) and the microfilm and microfiche machines.
The computers have both the CATNYP library online catalog and access to electronic resources. The electronic resources include Ancestry Library Edition, HeritageQuestOnline, Footnote.com, ProQuest Historical Newspapers, America's Historical Newspapers, Times of London, 19th Century Masterfile, New England Ancestors, New York County Histories Online, Origins Network and Burke's Peerage & Gentry Online.
I had hoped to find the book Colonial Families of Long Island, New York and Connecticut Being the Ancestry & Kindred of Herbert Furman Seversmith, by Herbert Furman Seversmith, FASG, published Washington DC, 1953. The NYPL had 6 volumes of it, and I checked out Volume 4, which contained information about my Lewis family. Unfortunately, it did not have information on the LaTourette family of Long Island. I copied the table of contents for all volumes and the Lewis information.