La Casa de Libro (255 Calle Cristo, Old San Juan, 787/723-0354, lcdl [at] prw [dot] net, www.lacasadellibro.org [1], Tues.–Sat. 11:30 a.m.–4:30 p.m., free) is a little gem of a museum in a former residence. It has an impressive collection of historic books displayed in exhibits that rotate about every three months. In 2005 it featured an exhibit honoring the 400-year anniversary of Cervantes’s Don Quixote that included a first edition from 1605.
Links:
[1] http://www.lacasadellibro.org