This is one of the five drinking spots within Bourbon & Branch(others are the B&B main bar, Russell’s Room, Wilson & Wilson, and The Ipswitch), and is the only one without the need for a reservation. Like any drinking venue there is a capacity limit so you may still have to wait in a line. However, most of my visits have been walk-ins and those were on weekend nights. If you show up to B&B without a reservation or do not know the entry-password, a doorman will direct you to the Library. The public/walk-in entrance is on O’Farrell Street at an unmarked door(it does not have its own address), and just steps around the corner from the B&B entrance on Jones St. Its other entrance is through B&B itself, if you’re already inside. The Library is dark, and does feel cramped and stuffy when crowded. There are very limited seatings with liquor barrels as tables. The shelves are lined with actual books. The bar itself has a limited menu than what is available at B&B, but that is still plenty if you have a group and can try everything. I seemed to always get the Rusty Nail here but they also do a really good Manhattan, or an Old-Fashioned(my choice is Four Roses or Woodford Reserve).