This Enhanced eBook includes a desktop version which may be used offline. Download the BOP (zip) file for use on either a Windows PC, or a Mac. For Android, download the app to your device. In both cases, use the unique keycode on the product page to gain full access to either version. If unsure, check the Help pages here.
It is a fantastic book, and very engaging. I need to get this in the hands of my students in Japan.