And if that's not enough, it comes with nearly a million lines of example code, that you can get at with three keystrokes; describe-function / describe-key (etc.), TAB (to select the link to the source code), ENT (to follow the link). From there, you can edit the code, press C-M-x, and immediately play with your changes. Emacs is written in Emacs Lisp, and you can view the code and edit it at runtime. This makes Emacs Lisp significantly easier to learn than pretty much anything else, where all you have books with snippets of code that nobody ever used or ever will use.
Emacs does not lack resources for learning Emacs Lisp.
I want to write a book that will get you to where you can profitably read the manuals.