This is a really great bar to stop into while exploring the South Side of Pittsburgh. Established and reputable, The Library is a very nice bar. The downstairs is generally busy; however, it's possible to get some peace and quiet if you head upstairs where they have another bar and even more rotating craft beers.
The craft beer selection is good and generally has good, reliable beers to try. When the draft isn't to your liking, check out the bottle selection.
Can't attest to the food as I haven't yet tried it.
One other thing to note was the fact that on my way out, the owner of the place ran downstairs to check his stock of beers that he keeps for himself and friends. Among them he found a 2010 Founders Breakfast Stout that he offered to me just because we had a good conversation about beer. He's a very generous guy and obviously cares for his customers and retains a passion for good craft beer. I'd recommend a place with such an owner to anyone. Be sure to check it out.