Tableau Desktop

full desktop environment for creating workbooks. Can create (normal) and packaged workbooks. Can upload to any server-side software

Tableau Server

used to Publish Dashboards

Tableau Reader

(free) - to open Tableau Packaged workbooks locally

Tableau Public

(free) - to create workbooks that you can ONLY upload to Tableau Public (see below), can ONLY connect to XLS or Text files. Can ONLY upload to Tableau Public