You can find the big book stores almost in every place in Bali. Those hunting the old books, you can go to Legian and find some favorite books which are worth reading, of course at affordable prices.
Some who are searching the book stores with the cozy lounges and café, they may find it in the malls or department stores around Denpasar or Kuta. Pamper yourself with the good books in good price, in a great environment.
