This book gave me the motivation to play with asterisk. It's a great toy, but capable of being much more in skilled hands. Had I reason to build a serious PBX this book gave me the background to do this.

The information is presented in a clear and logical format with a focus on the necessary concepts and then building your first configuration using the text configuration file. Also covered are options for hardware connectivity to the variety of physical interfaces that are avaialble and issues such as software vs hardware echo cancelling.

Security is covered as well as protocols used in internet telephony. With this background interconnection one asterisk box to another or to a service that supports the SIP protocol like skype or vonage is covered.

For the less geeky there is coverage of various turnkey asterisk packages with gui interfaces to get one up with a basic system quickly and without messing with text configuration files.

This book made playing with asterisk fun for me and it can be an essential resource for someone looking to roll their own pbx with ip or more traditional telephony.