Wordpress, how to start with an empty theme?

Question

I have been working on Wordpress for a month creating themes. Otherwise, when I'm starting a new project, I'm always starting with an existing theme that I am modifying.

What I want, is to clean perfectly a theme and add to it what I need for the website.

But, my Wordpress knowledge aren't enough to do it. So, I'm asking you if you know a great book, website etc, where they are explaining simply how to create a new theme (understand every features of Wordpress, explaining every functions in the functions.php file, how to add correctly Wordpress post content).

Thanks

Answer 1

Romain asked:

...how to create a new theme (understand every features of Wordpress, explaining every functions in the functions.php file, how to add correctly Wordpress post content).

Start with the codex http://codex.wordpress.org/Main_Page which is

the online manual for WordPress and a living repository for WordPress information and documentation.

Answer 2

What I did was create all the files and save them in a folder, then upload them as needed. I copied them from this simple tutorial and although says its to create a designed theme, it has nothing but basic blank theme:

http://blog.spoongraphics.co.uk/tutorials/how-to-build-a-custom-wordpress-theme-from-scratch