Background:
I'm mostly a vi user and am converting to Emacs.
Past the basics and now use it for writing code in C and some Python with plans to do an R conversion too.
I wrote (Common) LISP for years over two decades ago when I was in grad school but now I've severely lapsed (can write hello world but that's it).
Question:
What would you recommend for a guy in my position to get learning the Emacs LISP environment and start hacking Emacs.
Are there books, blogs, resources I should read, exercises I should do?