Tableau is a business intelligence and data visualization tool that allows users to make sense of their data through interactive charts, graphs, and diagrams. It has two main components: Tableau Desktop, which is used to connect to and analyze data and create visualizations, and Tableau Server, which is used to share visualizations and analyses across organizations. Tableau Server allows administrators to control access to content and projects through group and individual permissions. Both Desktop and Server require annual licenses but provide interactive dashboards, custom calculations, and easy drag-and-drop functionality for data exploration and storytelling.