The Avery Library announced on February 4 that its on-line trove of the Real Estate Record and Builders’ Guide, from 1868 to 1922, is officially available and searchable. A fantastic resource.
There is no longer any need to use the cumbersome process outlined in this 2009 post. The OMH Manhattan N.B. Database remains the only place to look up building permits directly, and it covers 1900 to 1986.
—–
[Update 11.10.2012: Broken link to RERBG fixed.]