A patent is a grant of property right by the government to an inventor which excludes others from making, using, or selling the invention. An inventor may assign the patent rights to his/her heirs or to another person or company (i.e., Sperry Marine Division). The Patent and Trademark Office is the agency responsible for examining each patent application to see if the invention is "new and useful" or that any improvements to an existing object are "new, useful, and unobvious." General information on patents can be found on the USPTO Patents web page.
An inventor must thoroughly research his/her invention (usually with the help of a patent attorney) to see whether it meets the above criteria. While a complete patent search cannot be conducted at Alderman Library we do have some of the tools that are necessary to begin a search. Virginia Commonwealth University Library, formerly a patent depository, has a very useful Patent page.