If you have registered your print version of your book on your account with oreilly.com, you are eligible for a $4.99 upgrade to the eBook version.
After you log into your account, go to "your products" and click on the "print books " tab. To the right of your registered books, you will see a yellow button that says: "$4.99 Ebook Upgrade". Hope that helps and have a great day!
Customer Service Representative