A Tableau Workbook (.twb) file contains all the information necessary to define a Tableau data visualization. It stores the worksheets, dashboards, and stories created in Tableau, along with the connections to the underlying data sources. However, it's important to note that the .twb file itself does not contain the actual data. Instead, it holds metadata about the data source, such as the server name, database name, table names, and any custom SQL queries used to retrieve the data. When you open a .twb file, Tableau connects to the specified data source and retrieves the data to populate the visualizations. This makes .twb files relatively small and easily shareable. They are essentially instructions for Tableau on how to connect to and visualize data. Sharing a .twb file allows others to view and interact with your Tableau visualizations, provided they have access to the underlying data source. If the data source is not accessible, the visualizations may not display correctly or at all. For sharing workbooks with data included, consider using .twbx files.