"Own Your Space--Keep Yourself and Your Stuff Safe Online"
Microsoft has released a free ebook covering a wide range of security topics. Although intended for teenagers, the book offers a solid enough look at using the internet safely, and it's suitable for anyone looking for a primer on internet security.
It's difficult to write books for teenagers that don't fall into the "trying too hard to be cool" trap, but Microsoft has done an admirable job. The text is a comprehensive guide for teenagers (and new computer users) that covers everything from how to spot phishing tactics to setting up your browser to protect against browser-based exploits to dealing with cyber-stalking and bullying. It also provides interesting history and real world examples of the harm that can come from security vulnerabilities.
Download the ebook @ Microsoft's Site