"one book store" is slightly unfair. You'll find a selection of popular cheap paperbacks at Carrefour, Lulu Hypermarket and some of the self-styled "bookshops". There's a small reading library at Garvey's, but most of the English readers I know stock up at LHR departures and then swop amongst themselves. Doha Players had most of the old British Council selection, but of course, that was destroyed by the bomb.