Not necessarily. You can read Ateneo e-books through any of the following programs:
1. For Windows (for PC) and OS X (for Mac), you can use Adobe Digital Editions, which you can download for free.
2. For iOS X (for iPad, iPhone), you can use PocketBooks and Bluefire Reader, which you can download for free from iTunes.
Be sure that you authorize your reader app to your Adobe ID. For instructions on how to register your app, click on the links above.