Do you know that Narita Anime Deck is still open? Last I heard was that Narita Anime Deck closed last year.

There are bookstores at NRT, Terminal 1 gate area and Terminal 2 gate area.

I see that you are from Los Angeles area, I lived at Hermosa Beach for more than a decade. In Los Angeles area there are Japanese bookstore Kinokuniya and Book-Off. These bookstores do have very good selections serving Japanese expatriates living in the Los Angeles area. I know at Kinokuniya you can order any currently published books in Japan. Kinokuniya can look up online for and tell you at spot if a book you are looking is current published and available.