ricland, please take no offense in this and please please please try not to offend all these hardworking XOOPS dudes. It isn't that hard, you know?
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Hi there, ric.
Can you please be a bit more polite? You bring many important points up, but you screw up big time bullying and barking like this . It's easy to imagine scenarios in which you are either very happy or very angry with XOOPS docs this time next year and nobody cares to read or reply to your posts due to your delivery.
Now, lemme try to give you some directions on how to get this work done (and hopefully a better understanding of what goes on here and in OSS in general)
First off, you can simply get the relevant material you need from the forums, from comments inside .php files, modules' readme files, the wiki (I've just tried to fit all the wiki based info in one big page... not very successful, but makes it easier for you anyway), mailing lists, published document(s), other information sources such as the All about XOOPS link over there. If you'd rather have this compiled, either wait for someone with enough free time to do so to volunteer or add a couple of days to your Tutorial/Manual schedule and compile it yourself.
Then you can focus on writing. You should try write material that's useful for all XOOPS's users, from UbberGeeks to AOLers and from first timers to XOOPS hackers. That is, it should ideally be a good introduction, reference, tutorial and whatnot. It's up to you to decide whether a "What is a CMS?" and/or a "Extending objects" section would fit in your doc, but rest assured that literally thousands of users will read it and some dozens will give you feedback. And a couple of people will come to you with a "Hey, I always thought you'd have to be from government to have such a chimp-like writing talent" or "Can you tell me where you live so that I can beat your dog because you said something wrong about Smarty?" attitude
One of the many factors that makes writing documentation harder: would you rather have a very well documented half-baked CMS (== lots of time to compile information scattered all around) or a secure, fast and reliable system that has a somewhat chaotic but greatly (and quickly) improving documentation? It's wonderful that some people can focus on documentation, some other (like myself) on translations, and some other on coding.