The Robinson Atlas will help you to date the construction of a building (e.g. it appears in the 1905 Baist Atlas atlas but not in the 1887) and give you a picture of neighborhood development. These maps also show the legal description (addition name, lot, and block numbers) of your building, which is necessary for locating many historic building records.
Beginning April 20, the 2nd and 3rd floors of the Blair-Caldwell Branch Library are closed. The archives and book collection on 2nd floor are in the process of being moved to Central Library where they will be available via the Special Collections Reading Room on 1st floor starting May 1.