A good start would be the following books:
And the DOM (Document Object Model) documentation here (especially the chm files):
For German readers also:
I don't know if you have any experience with scripting in general.
But if you don't have any and you work on mac, then "applescript for absolute beginners" by Bert Altenburg is a good start.
I used that some years ago to get started.
I had problems with the other resources because i had no general programming experience.
After reading that book, you have some basics and it's easier to focus on Indesign.
Also applescript is very easy to start with. It reads like english
The title Luc mentioned above, "AppleScript for Absolute Starters," is a free PDF that can be downloaded here:
It isn't specific to scripting InDesign; it's more of a general discussion of the AppleScript language. If you want to delve deeper, I like Sal Soghoian and Bill Cheeseman's "AppleScript 1-2-3." Again, not specific to InDesign, but tons of great information about the language.
I finally got around to buying the Peter Kahrel book. Just wanted to say thanks and hopefully I won't be asking so many questions from now on!
Have a great day!!