Growth of broadband communication networks and multimedia data have made it possible for consumers from all over the world to create, exchange, and edit digital data. This has led to concerns with copyright protection and maintaining privacy, giving rise to a new area in security research - Steganography. Until recently, steganographic techniques received much less attention from the research community and the industry than cryptography. Research in steganography has, in the past few years, grown exponentially. A large number of steganographic systems have been proposed, and there are a number of interesting research directions. One of these directions is in the field of audio data hiding. In this book, we look at, and measure key requirements for successful data hiding, and propose improvements to two audio data hiding techniques, namely LSB embedding and echo hiding.The measurement of these key requirements should help shed some light on enhancements to data hiding and would be especially useful to professionals in communications, computer security, or anyone else interested in data hiding.