It's certainly a great resource and extremely comprehensive. Personally I think it a bit too detailed to be an effective beginner's guide.

And I say this as one of the credited authors of the LaTeX wikibook (https://en.wikibooks.org/wiki/LaTeX/Authors)

Therefore I'd still plug my own Getting to Grips with LaTeX as a good starting point for newbies: http://www.andy-roberts.net/writing/latex/

I promise that's my final plug :P Quite frankly I'm just happy people want to learn LaTeX other word processors.