An inventor is a person which creates new inventions, typically mechanical or electrical machines or other devices of practical use. Though some inventors may also be scientists, most base their work on the discoveries of other scientists, experimenting with practical applications and combinations of those discoveries, and with improvements and combinations of existing devices, to create new useful devices.
The system of patents was established to encourage inventors by granting limited-term monopoly on inventions that are judged sufficiently novel. This system is nowadays frequently abused, especially in the United States, and many people have called for reform or even abolition of the patent system. In the U.S., however, the patent right originates from the Constitution, so inventors will likely continue to protect their inventions that way for many years to come.