James S. Tiller 
The Ethical Hack [PDF ebook] 
A Framework for Business Value Penetration Testing

This book explains the methodologies, framework, and ‘unwritten conventions’ that ethical hacks should employ to provide the maximum value to organizations that want to harden their security. It goes beyond the technical aspects of penetration testing to address the processes and rules of engagement for successful tests. The text examines testing from a strategic perspective to show how testing ramifications affect an entire organization. Security practitioners can use this book to reduce their exposure and deliver better service, while organizations will learn how to align the information about tools, techniques, and vulnerabilities that they gather from testing with their business objectives.