* Explains exactly what steganography is-hiding a message inside an innocuous picture or music file-and how it has become a popular tool for secretly sending and receiving messages for both the good guys and the bad guys * First book to describe international terrorists' cybersecurity tool of choice in an accessible language * Author is a top security consultant for the CIA and provides gripping stories that show how steganography works * Appendix provides tools to help people detect and counteract stenanography