The Authors module displays a collection of the site’s authors, and it gives you the possibility to choose between showing all authors, or just a specific selection of them, in any particular module. Next to each author’s thumbnail you can display his/her bio, and the contact methods filled in in Users » Your Profile.
Note: The image that gets shown for each author is its Gravatar. Visit this link for more information on how to get a Gravatar.
Please note: the modules availability and their specific settings depend on each theme, not all themes include the same modules with the same settings.