Typically, raw data obtained for a GIS project needs to be massaged for use in the specific application. It may need to be merged, converted to a different geometry type, saved to the coordinate reference system of the project, subset to the extent of the study area, or subset by attribute values. While QGIS provides a powerful set of tools that can handle many types of vector preparation and transformation tasks, this chapter will cover what we consider to be commonly used vector-preparation tasks. Many of the tools covered in this chapter are found on the Vector menu in QGIS; however, others are available in the processing toolbox. Additional vector processing tasks will be covered in Chapter 7, The Processing Toolbox and Chapter 8, Automating Workflows with the Graphical Modeler. The topics that we will cover in this chapter are as follows: