The procedure for granting patents, the requirements placed on the patentee, and the extent of the exclusive rights vary widely between countries according to national laws and international agreements. Typically, however, a patent application must include one or more claims defining the invention which must be new, non-obvious, and useful or industrially applicable. In many countries, certain subject areas are excluded from patents, such as business methods and mental acts. The exclusive right granted to a patentee in most countries is the right to prevent others from making, using, selling, or distributing the patented invention without permission. It is just a right to prevent others' use. A patent does not give the proprietor of the patent the right to use the patented invention, should it fall within the scope of an earlier patent.

Under the World Trade Organization's (WTO) Agreement on Trade-Related Aspects of Intellectual Property Rights, patents should be available in WTO member states for any inventions, in all fields of technology, and the term of protection available should be the minimum twenty years. Different types of patents may have varying patent terms (i.e., durations).

Etymology
The word patent originates from the Latin patere, which means "to lay open" (i.e., to make available for public inspection), and more directly as a shortened version of the term letters patent, which originally denoted an open for public reading royal decree granting exclusive rights to a person.

History
U.S. Patents granted, 1790–2008.
Patents in force in 2000In 500 BC, in the Greek city of Sybaris (located in what is now southern Italy), "encouragement was held out to all who should discover any new refinement in luxury, the profits arising from which were secured to the inventor by patent for the space of a year."

The Florentine architect Filippo Brunelleschi received a three-year patent for a barge with hoisting gear, that carried marble along the Arno River in 1421. In 1449, King Henry VI granted the first patent with a license of 20 years to John of Utynam for introducing the making of colored glass to England.

Patents in the modern sense originated in 1474, when the Republic of Venice enacted a decree that new and inventive devices, once put into practice, had to be communicated to the Republic to obtain the right to prevent others from using them.

England followed with the Statute of Monopolies in 1623 under King James I, which declared that patents could only be granted for "projects of new invention." During the reign of Queen Anne (1702–14), the lawyers of the English Court developed the requirement that a written description of the invention must be submitted. The patent system in many other countries, including Australia, is based on British law and can be traced back to the Statute of Monopolies.

In France, patents were granted by the monarchy and by other institutions like the "Maison du Roi". The Academy examined novelty. Examinations were generally done in secret with no requirement to publish a description of the invention. Actual use of the invention was deemed adequate disclosure to the public. The modern French patent system was created during the Revolution in 1791. Patents were granted without examination since inventor's right was considered as a natural one.

In the United States, during the so-called colonial period and Articles of Confederation years (1778–89), several states adopted patent systems of their own. The first Congress adopted a Patent Act, in 1790, and the first patent was issued under this Act on July 31, 1790 (to Samuel Hopkins of Vermont for a potash production technique).