Company is an auto-completion library for Emacs. It has a wide variety of back-ends. See http://company-mode.github.io

(require-package 'company)

This company-quickhelp package may end up annoying me greatly, but I'm giving it a try. It shows help documentation alongside completion entries for those that support it (like elisp).

(require-package 'company-quickhelp)

(if (require 'company nil 'noerror)
    (progn
;      (add-hook 'after-init-hook 'global-company-mode)
;      (company-quickhelp-mode 1)
;      (setq company-begin-commands '(self-insert-command))
      ))