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> what is a good book that explains the whole DDR/Backup/WAN/Dial-In|Out
> environments ?

I don't have a book to recommend...

> I also heard that there are 4 DDR Methods (Dialer Profiles)
>
> 1. dialer map
> 2. dialer interfaces
> 3. ?
> 4. ?

There are 2 types of DDR:

1. Legacy DDR
2. Dialer Profiles

Each has implementation details unique to them:

1. Legacy
dialer map (in or out)
dialer string (in or out)
nothing (in)
2. Dialer Profiles
bind by CLID (in)
bind by Authenticated name (in)

Each support the different dialer features, like timers, backup, hold-
queue, etc.

Dialer Profiles are only useful is you need/want per-user granularity
and
don't wan't/can't use AAA to provide it. Otherwise, Legacy DDR is more
than sufficient and simpler.

Yes, a nice book or better documentation would be helpful. The
generalities
of the features aren't too hard to grasp, but it's easy to get complex
quickly, and add in different sub-features and things can get confusing.

Here is one less-than-lame page on DDR:

http://www.cisco.com/cgi-bin/Support...Network_Design

And here is a good link discussing the different backup options:

http://www.cisco.com/en/US/customer/...8009457d.shtml

Hope that helps; let me know if you have more questions.

mark