There are several methods available in VMD for the user to control and interact with the molecular display. The primary methods are by using the mouse, either in the VMD graphical display window (where the molecule is displayed) or in the different graphical user interface (GUI) forms provided by the program. There is also a third user interface component, the text console interface, in which the user can enter and execute simple commands or more sophisticated VMD scripts. Also under development, but not documented here due to their experimental nature, are user interface components based on three-dimensional input devices and on speech- and gesture-recognition systems. This chapter describes how to use the mouse-based user interface components; it describes the basic operation of the graphical user interface components, and gives a quick overview of each available form. In VMD, the GUI is composed of several distinct windows, called forms, which provide a set of buttons, sliders, choosers, etc. to control some specific element of the program. The other primary user interface component, the text user interface, is described fully in chapter § .