3.4 What is my init file?

When Emacs starts up, it attempts to load and execute the contents of a file commonly called .emacs (though it may have other names, see Where do I put my init file?) which contains any customizations you have made. You can manually add lisp code to your .emacs, or you can use the Customization interface accessible from the Options menu. If the file does not exist, Emacs will start with the default settings.