Well, that's why there is several documents: C-h i

* Elisp: (elisp). The Emacs Lisp Reference Manual.

* Emacs Lisp Intro: (eintr). A simple introduction to Emacs Lisp

* Emacs: (emacs). The extensible self-documenting text editor.

* Emacs FAQ: (efaq). Frequently Asked Questions about Emacs.

And that's not even looking at specialized documentation such as the one for Gnus, for Widget, for Dired-X, for Ediff, ...

I agree with parent, Emacs documentation is some of the best I know and easily searchable.