Automobiles are a complex technical system composed of subsystems with specific design functions. The heart of every automobile is its engine, which produces the power to drive the wheels and electricity for the lights and other systems. Other important subsystems are those that control and steer the vehicle, and make it comfortable for passengers. Research and development engineers work to improve the body, chassis, engine, transmission, controls, safety systems, and emissions-control systems of automobiles.

Many people use automobiles as their primary mode of transportation. They help millions of people around the world get to work, school, and other places where they need to go. Automobiles also provide opportunities to visit and explore new places.

The history of the automobile began in the late 1800s with the invention of the internal combustion engine fueled by gasoline. By the 1920s, Henry Ford had innovated mass production techniques that enabled him to dominate the automotive industry with his Model T car. These techniques were adopted by other American producers, and the number of manufacturers dwindled to a few large companies that today are known as the Big Three automakers.

Modern automobiles have advanced in a variety of ways that reflect the needs and preferences of consumers. Some of these innovations have made the cars more fuel-efficient, easier to operate, and more comfortable for passengers. Other developments have addressed social concerns, such as air pollution and the number of substances emitted into the atmosphere. Other changes have been the result of government regulations affecting vehicle safety, fuel consumption, and emissions.