I purchased the Kindle edition of the book on Amazon.com. The Kindle edition is no longer for sale, but Barnes and Noble still sells it for Nook. You would need a tablet (like an iPad or Android Tablet) that supports the Nook app or a Nook Reader.
If you’re not in a terrible hurry, I believe he is working on an updated copy right now. The current copy is somewhat obsolete with the updates to Inform since it was published.