Havana  is desperately in need of a Barnes & Noble, and newspapers or magazines are sold only in a few tourist hotels.
The Instituto Cubano del Libro (Cuban Book Institute, O’Reilly #4, esq. Tacón, tel. 07/863-2244, Mon.–Sat. 10 a.m.–5:30 p.m.), on Plaza de Armas  in the Palacio del Segundo Cabo, has three small bookshops; most books are in Spanish.
The plaza is also the setting for the Mercado de Libros (Wed.–Sat. 9 a.m.–7 p.m.), a secondhand book fair where you can rummage through a dreary collection of tattered tomes.
Librería La Internacional (Obispo #528, Habana Vieja, tel. 07/861-3238, daily 10 a.m.–5:30 p.m.) stocks a limited selection of texts in English, plus a small selection of English-language novels.
La Moderna Poesía (Obispo #527, esq. Bernaza, tel. 07/861-6983, Mon.–Sat. 10 a.m.–8 p.m.) is Cuba’s largest bookstore, although virtually the entire stock is in Spanish.
La Papelería (O’Reilly #102, esq. Tacón, Habana Vieja, tel. 07/863-4263, Mon.–Sat. 9 a.m.–6:30 p.m.), cater-corner to the Plaza de Armas, sells pens and other office supplies.
Librería Fernando Ortíz (Calle L, esq. 27, tel. 07/832-9653, Mon.–Sat. 10 a.m.–5:30 p.m.) is your best bet for English-language books. Its meager collection spans a wide range.
Librería Centenario del Apóstol (Calle 25 #164, e/ Infanta y O, tel. 07/870-7220, daily 9 a.m.–9 p.m.) has used texts.
Ofimática (tel. 07/204-0632), in Edificio Habana in the Miramar Trade Center (3ra Av., e/ 76 y 80, Miramar, Mon.–Fri. 8 a.m.–6 p.m.), sells computer and office accessories.