Here's an extract:
Although attacking networks can be fun and informative—not to mention illegal if you do not have all the proper permissions—the fact remains that the vast majority of us do not need to know how to do so. Frankly, becoming a good penetration tester (pen tester) takes more than a week-long class. It takes commitment, dedication, intuition, and technical savvy, not to mention a blatant disregard for the rules and the right way to do things.
Read the entire excerpt here..