[OS X TeX] Vertical space

[Alain Schremmer]

Where can I find some information about the way to control vertical  
space? (I cannot predict the effect of the various commands I use, in  
particular \\[length]?)

I have looked in Companion II which does not seem even to mention \\ 
[length], and googled some. I found some interesting sites, e.g. < http://www.maths.tcd.ie/~dwilkins/LaTeXPrimer/WhiteSpace.html 
 > and <http://www.personal.ceu.hu/tex/spacebox.htm> but, that I can  
see, none mentions \\[length] nor do they quite explain the  
differences between requiring a particular vertical space, say, after  
a paragraph, after an item in a list or after a table, etc which I  
suspect is of the essence.

I am really not asking for an explanation because I can always fudge  
something so that there is no emergency of any kind but whether  
anybody knows of some explanation, somewhere because it annoys me  
having to resort to blind experimentation and not really knowing what  
I am doing.

Curious regards
--schremmer