All the other Emacs cheat sheets are too exhaustive and cumbersome. This is for people who just need to get in, make a few edits, and get out. This is not intended to be a guide for the power user or developers.
mu4e (mu-for-emacs) is an e-mail client for GNU Emacs version 24.4 or
higher, built on top of the mu(1) e-mail search engine. mu4e is
optimized for quickly processing large amounts of e-mail.