They have Maurice Sendak’s original manuscripts and original drawings, and it is a magical place. I went to a special Where the Wild Things Are exhibition a couple of years back, and it was truly just great.
I saw that tremendous special exhibit, too. The Rosenbach Museum & Library is a jewel of a place, of special interest to lovers of art & literature alike. Make a point to attend their Bloomsday festivities, held every summer on June 16th.