BOOKasahi.com
Book reviews include e-books. Search newspaper advertisements for books.
Book Sellers Catalogs
Book sellers (commercial bookstores) provide extensive catalogs including e-books, DVDs, videos and more. You can also order books online. Here are some leading online bookstores in Japan:
Jinbocho Book Town/神保町 Jinbocho, Tokyo is the most famous town for used books. This database allows you to search used books at over 50 used book stores in Jinbocho.