The Library, in the NoMad Hotel in Manhattan, is a two level library with fully curated volumes that cover everything from the history of New York to the history of classic cocktails.
It is #3 on this list: Welcome to the World of Library Bars (there are some other neat ones too)
Post script: this one fooled me. It's in a new hotel, they filled it with old stuff. Still interesting, but hardly iconic - yet!
I have sought out and visited a few iconic and historic bars in my travels, and have found the experiences to be memorable. And definitely worth the effort:
Here are my blog posts about a few:
Harry's Bar in Venice, where they invented the Bellini.
The Campbell Apartment (in Grand Central Station) in New York City, which is in Grand Central Station.
Le Jules Verne in Paris.