[NTG-context] ConTeXt book

[Ernesto Schirmacher]

Dear ConTeXt experts, 

I recently switched over to ConTeXt and it has been great!

I have been learning a lot from the source files in texmf/tex/context/base/
but I find it hard to understand from the code for a given command what
options are available, which ones are defaults, and what are all the possible values
one might give a given option.

I presume all this information is contained in the sources but I am unsure 
as to what I should be looking for.  Are there specific things I should be
looking for?

Thanks in advance,

Ernesto