The mouse was invented in the 1960s at Stanford University and helped popularize graphical user interfaces. It controls an on-screen pointer to select items, access menus, and interact with programs. Early mice were blocky but evolved into sleeker designs from many companies. The mouse established computers as tools for graphics and popularized input techniques like clicking, dragging, and right-clicking. Variants include trackballs, trackpads, and keyboard pointers for less space than a traditional mouse.