There are lots of ways to read a Kindle book even if you don't own a Kindle. If you go to http://read.amazon.com and log in to your amazon account, you can read your entire library right in the browser. Amazon also has free apps for your Windows PC or Mac.
Go to http://amazon.com/gp/kindle/pc and provide your email address or mobile phone number to get either an email or a text with a link to get the app for your device, or search in the app store for your mobile device with the search word "Kindle" to get the Kindle app and start reading.
To buy the book, click here.