People who have been using Emacs for a while often develop the desire to learn Emacs Lisp, so they can customize Emacs more extensively, develop extra packages and create the ultimate editing experience, uniquely tailored to their needs & preferences.
There are a ton of Emacs Lisp resources our there, but most people
generally need only one - the official
Emacs Lisp manual. It’s
bundled with Emacs and you can start reading right away by pressing
C-h i m Elisp RET. If you’re relatively new to programming in
general you might also check out the
Introduction to Emacs Lisp
C-h i m Emacs Lisp Intro RET), before diving into the manual.
There are also plenty of Emacs Lisp tutorials online, but I’d advise against using them, as most of them have never been updated after originally published and Emacs Lisp keeps evolving all the time (albeit not as fast as I would have liked it to). That being said, Learn Emacs Lisp in 15 minutes is a short and sweet intro to the language. You can find more online educational resources on the EmacsWiki.
Trust me on this - any time invested in learning Emacs Lisp will be time well spent!