Here goes for Madrid:
Booksellers —This is one of the most important English-language bookstores in Madrid. Monday-Friday 9:30 am-2 pm and 5-8 pm, Saturday 10 am-2 pm. Jose Abascal 48. Phone 91-442-8104.
El Corte Inglés Bookstore—They sell books, books on tape, CDs and related items. Monday-Saturday 10 am-9:30 pm and the first Sunday of each month 11 am-8 pm. Fuencarral 118. Phone 91-447-2343.
FNAC —The biggest and most modern downtown bookstore has a sizable English-language collection and also sells music and computer equipment. Monday-Saturday 10 am-9:30 pm, Sunday noon-9:30 pm. Calle Preciados 28. Phone 91-595-6200.
I copied all the above from
http://europe.cnn.com/TRAVEL/CITY.GUIDES/WTR/internat.profiles/ip.madrid.html It has a very nice collection of information on Madrid.
And here's some more:
Casa del Libro (Gran Via, 29). Mostly new Spanish books, with an English section.
Turner English Books (Genova 3, 28004). New books in Spanish, English, and French. Also has a video rental collection, including many British films.
(These two came from
http://www.geocities.com/Athens/4824/eu-misc.htm#madrid ) These are the two stores I used to buy books in. Turner's in particular has been pretty famous for many years as the place not only to buy books, but to post messages on their bulletin boards for apartment sharing and private classes / language exchanges.
[ 06-11-2001: Message edited by: MadridMan ]