Is there an official manual that defines how all this stuff works?

1) What modules call what... in what order when executed.

2) What variables are avail when where and why

3) what needs to get past to each module to carry security
and permissions from screen to screen

I'm looking for a list of 'syntax' of calls to all the various scripts...
just like you'd see in any programming book. Somthing that would
help explain the modules

Something... anything!