We visited here a few years ago, and decided to visit again. They have a few rooms on the second floor where they have particular exhibits and we went to see the one now on view. At 4 pm they were offering a tour of the private home portion of the building where the Rosenbach brothers lived - we had an excellent and very knowledgeable guide. We love books and the chance to even be in the same room with rare treasures is a treat. It's not far from Rittenhouse Square so it's a lovely place to spend an hour whatever they have on exhibit.