Shakespeare a synové was one of the original places to find English (and other language) new and used books in Prague. Though their Vinohrady location is no more, they still have an active and packed store in Mala Strana, filled with all the new books and classics.
If you're looking for something to read and still lost in with all marks above Czech writing, make this bookstore your first stop. The place also has browsing room downstairs, so feel free to read up even if you're not in the mood for a purchase.
Look downstairs for the used books! Check online for ebooks!
Su-Sa: 11:00-19:00