Where is an elegant summary of what Asterisk is?

[V. Bruce Hunt]

I'm new to Asterisk and want to know what it is and what it does and why one would want to use it. Does such documentation exist? If so where can it be accessed? I found all sorts of docs that assume one knows what Asterisk is and provides lots of structural and configuration detail but no overview of its reason for existing? Can someone point me in the right direction?

[Gernot]

You can most probably find what you are looking for on the original Asterisk website, Asterisk - Get Started:

http://www.asterisk.org/get-started