I like to alternate between English and Turkish books, sometimes within a half hour train commute. I refer to it as taxing my brain and have a vague notion, although without any data to back it up, that switching between texts written in different languages may help keep one's mind sharp. If I knew a 3rd language, I would add that to my reading schedule too.
For about 2 years now I have been ordering Turkish books from Pandora, a bookseller based in Istanbul. Although shipping costs are sometimes as expensive as the books themselves, Pandora's service has so far been reliable. They also have a store in Istanbul, which I visited when I was there last May. It was disappointingly small, but the employees were very helpful and they had the books I was looking for.
Even though I already have a shelf-long backlog of both English and Turkish books to read, I couldn't resist the urge to order more books from Pandora less than 10 days ago. They arrived today despite the fact that they were shipped by surface mail.
The new additions to the backlog are a small book about the structure of scientific thinking during the Ottoman period, the latest issue of a literature magazine featuring several cat (kedi) stories and another book about the history of the Greek residents of Büyükada (Prinkipo), one of the islands off Istanbul. I have written about Büyükada in this post and in this post and in this post.