A patent is a government granted right for a fixed time period to exclude others from making, selling, using, and importing an invention, product, process or design, or improvements on such items.  These exclusive, monopoly rights are powerful, and in return the inventor is required to describe the invention in writing.  The end result is simply a written description, accompanied by diagrams and drawings, that explains the invention. The public benefits because anyone can read the details of the invention and improve upon it. Importantly, the patent not only allows the public to gain an understanding of the invention, but also defines its limits.