Every Emacs user knows that Emacs ships with plenty of built-in documentation in the GNU info format (they don’t call it a self-documenting editor for no reason). Most Emacs users know how to access that built-in documentation with C-h i (M-x info) and some Emacs users even know that the Emacs manual can be opened directly with C-h r (M-x info-emacs-manual).

If you know the name of the manual you’re looking for, however, there’s a nice little-known alternative to using C-h i - the info-display-manual command. When you run it you’ll be prompted in the minibuffer for the name of the manual you’d like to view (manual name completion is available).

To give you a more concrete example of the command’s advantage over info let’s try to open the Emacs Lisp manual with both commands. With info you’ll have to type the following:

M-x info RET m elisp RET

And the alternative would be:

M-x info-emacs-manual RET elisp RET

If you like the command I’d suggest binding it to some keybinding:

(define-key 'help-command (kbd "C-i") 'info-display-manual)