The Asterisk Handbook project is located at Asterisk.org

There you'll find pointers to the Asterisk handbook beta as an Acrobat PDF file.

• Asterisk
• Asterisk handbook (PDF)

I made a version of the handbook with hyperlink table of contents. It will save you a lot of page turning. It's also a megabyte smaller even though the contents are identical. {Update: I just noticed I'm not permitted to do this. I'll try to get Digium to post it.}

• Asterisk Handbook (2nd Draft) with Index (PDF)