Book excerpt: Most companies are using inefficient computer security defenses which allow hackers to break in at will. It's so bad that most companies have to assume that it is already or can easily be breached. It doesn't have to be this way! A data-driven computer security defense will help any entity better focus on the right threats and defenses. It will create an environment which will help you recognize emerging threats sooner, communicate those threats faster, and defend far more efficiently. What is taught in this book...better aligning defenses to the very threats they are supposed to defend against, will seem commonsense after you read them, but for reasons explained in the book, aren't applied by most companies. The lessons learned come from a 30-year computer security veteran who consulted with hundreds of companies, large and small, who figured out what did and didn't work when defending against hackers and malware. Roger A. Grimes is the author of nine previous books and over 1000 national magazine articles on computer security. Reading A Data-Driven Computer Security Defense will change the way you look at and use computer security for now on.