Info

Info' is the Help browser in GNU Emacs. Think F1.

M-x info-apropos

Don't know where to go. Try this command. For example, try M-x info-apropos RET compile RET to get some overview of compilation support in Emacs. For those people who want to work, before getting degrees.

[C-h r] (or M-x info-emacs-manual)

Learn how to use GNU Emacs. For those people who want to get degrees, before starting to work.

[C-h i] (or M-x info)

See manuals of all packages that come with your GNU Emacs

[i]

While in an info buffer, jump to some topic of interest. To learn about regular expressions try [C-h r] and {{Keys|i regular TAB}.

[I]

Same as [i] but gives you a list of links.

[L]

For the navel gazers. You are lost and overwhelmed by the amount of information available and you want to reflect on where all you went and how you got lost.

[C-u C-h i]

You have installed a Third party package. You have created an info file with make info' and want to browse the info file without much fuzz. You can M-x customize-variable RET Info-directory-list if you can get around to it. But it will take some time.