The applications chapter is where the various tools and techniques come together, and where various well known techniques such as ``phase vocoding'' are discussed. It is a good idea to scan Chapter 9 now to get a feel for practical techniques in common use. If this book were written according to the principles of ``backward education,'' we would begin with Chapter 9, and each first mention of an audio signal processing tool would refer to its coverage in a later chapter (or appendix). This is how the Web version of this chapter is intended to function (via hyperlinks).