This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
The only prerequisite for reading Beginning Java 7 is to have some basic programming experience, to be comfortable working in a command-line environment, and to be passionate about learning. I've tried to cover all necessary topics and in a manner that flows smoothly from the start of the book to its end.
In my opinion (and others may differ), you don't need to know about previous Java versions to get the most out of this book.
All the best.
subject: What are the pre-requisite for reading Beginning Java 7