What should you know to read this book? You should be aware that testing is not a “phase,” where software developers “throw the software over the wall” to test engineers when the developers have finished coding. To be cost effective, testing needs a life cycle that runs concurrently with the software development life cycle. The testing life cycle begins during the requirements elucidation phase of the software development life cycle, and concludes when the product is deemed ready to install or ship following a successful system test (or whatever you call the final test in your culture).
Ideally, you should be aware of the importance of test documentation, especially a formal test plan, in your life cycle. You should be aware that there are good standards for this documentation in the software industry; I strongly recommend the IEEE Software Engineering Standards collection in general, and IEEE-Standard-829, the Standard for Software Test Documentation, in particular.
Finally, you should have the desire to improve your knowledge of the testing process, and a commitment to make improvements.