United States has the most expansive patent subject matter in the world. US Patent Office has granted patents to living organism, computer software, business methods, new alphabets and countless.

Article 1 Section 1 Clause 8 of the US Constitution empowers the congress to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries. In furtherance of the power granted by the constitution, the US Congress enacted the first patent act in the year 1790. Though the act was amended several times, the most important amendment came about in the year 1952, when congress passed a new patent act codified under Title 35 of the United States Code. Though a few changes were made in 1986, 1996 and 1999, most provisions of the 1952 Act are still in effect.

The US Patent Law is based on the utilitarian reasoning, which is to promote the progress of science and useful arts in general public interest. An inventor gives an invention to the public and gets exclusive rights over it for a limited period of time. By granting exclusive rights to inventors for a limited period of time, the patent law provides incentive to invent, invest, design around and disclose which in turn encourages progress of science and technology.