As far as I know, before the Carnegie Library opened the only "public" library in town was the Young Men's Library founded in 1867 and by 1884 it had over 11,000 volumes. Google Books has the catalog from that year online:
1884 Catalog

It starts off describing the membership rules and talks about dues but the esteemed Mr. Garrett actually says the prices: $2 a year or a life-time membership for $25. He also mentions the location at that time: a new building on the south side of Decatur Street between Pryor and Central. Can't find a photo of the building, but here's the Sanborn fire map from 1886. 


Another treat: after the catalog there are 10 or so pages of vintage ads at the end.

Anyways, I've managed to distract myself entirely. The Carnegie Library was organized on May 6, 1899 with a donation of $145,000 from Mr. Carnegie. The building was designed by Ackerman and Ross of New York and opened to the public on March 3, 1902. Here she is:


And here's all that's left of her at the corner of Peachtree and W. Peachtree (pic thanks to debaird)


This photo ran in the paper the other day of Marcel Breuer posing with his model that replaced the Carnegie


Apparently this was his last major project before he died in 1981. I've always been pretty ambivalent about the hulking thing but it is what it is. Did you know there used to be a nice little restaurant in the downstairs lobby? It was called Delectables and Christiane Lauterbach gave it a pretty good review. She says they had an outdoor patio too, so I assume that was over the section that got renovated along Forsyth a few years ago. Bummed I missed it!

Fulton Co commissioner Robb Pitts has an idea to build a new replacement library of the future. He posted these recent buildings as examples of what we could have: 

Library Examples