Asterisk: The Definitive Guide is a solid text with good information for users and potential users of the Asterisk software.
While the preface indicates that the book takes a gentle approach to the Asterisk novice, the experience will be better if the reader is familiar with telephony terminology at a basic level. Basic Linux sysadmin skills are assumed, with CentOS and Ubuntu used for the example installations.
After a short history of Asterisk and its ecosystem, the book moves on to fairly detailed installation and configuration on a “clean” server. The approach used is retrieve source code from the Subversion repository and compile, rather than rely on (probably) outdated system packages.
Subsequent chapters cover Asterisk configuration options in detail, with all the primary areas of interest represented, starting with dialplan basics, voicemail, fax, etc.
A feature which I appreciated was the use of visually distinct sections, set off by a “bear trap” icon, to warn of pitfalls that commonly ensnare users or administrators, e.g., internet access is required when running the “make install” command for DAHDI, as this will try to download drivers from the Digium site. Trivial for home users, frustrating for corporate admins running the install in a disconnected lab if an unexpected failure occurs.
Recommended addition to the bookshelf of any sysadmin dealing with Asterisk and / or telephony in general.