The IP telephony Cookbook is divided in chapters which guide the reader through an increasing knowledge of the IP telephony. This first chapter contains introductory information and details the contents of Cookbook, moreover useful tips on how to read this document and techno-economic considerations are provided. The Chapter 2 explains the technology background needed in order to understand the topics addressed in the all Cookbook; in this chapter the basic IP telephony components are described and an overview about the IP telephony protocols is given. Chapter 2 ends with additional considerations on call routing and perspectives about the future. Chapter 3 gives an high level overview of scenarios a user may face when building an IP telephony environment, details are given in order to explain what a particular scenario is, what is needed in order to deploy it and why users should go for it. The next three chapters (Chapter 4, Chapter 5 and Chapter 6) detail how to set up IP telephony services; those chapters give the reader the chance of learn how to set up basic services, advanced services (even if still telephony centric) and value added services (where value added is intended with respect to the classic telephony service). Chapter 7 is about Global telephony integration, this chapter details the technology solutions in order to have a global IP telephony integration and a successful replacement of the classic telephony, moreover reports on the today's situation as well as migration and future trends are given. The last chapter contains regulatory/legal considearation users have to be aware when moving from classic telephony to IP telephony, the topics here described are relative to the regulation of IP telephony in Europe and in other countries out of the EU. A large number of classic telephony legal issues will be detailed (from Licensing to Unbundling) mapping them to the IP world. Moreover, the IP telephony Cookbook contains two annex: Annex A and Annex B. While the Annex A is focused to list and describe (briefly) the current and future IP telephony Projects in Europe to learn from, the Annex B gives the reader useful information about IP telephony hardware and software reporting "hands on" experience (i.e., reports on how the devices either did or did not work, how was tech-support, what were workarounds for the problems, etc).