A rentier (prounounce /rɛn'tje/) is an individual who depends on income derived from rents, which in turn are defined as “a reward for ownership of all natural resources” or the “income derived from the gift of nature.” A rentier state is a term in political science and international relations theory used to classify those states which derive all or a substantial portion of their national revenues from the rent of indigenous resources to external clients. The term is most frequently applied to states rich in highly valued natural resources such as petroleum, however it could also be applied to those nations which trade on their strategic resources (such as permitting the development of an important military base in their territory). Dependent as they are on this source of income, rentier states may generate rents externally by manipulating the global political and economic environment. Such manipulation may include monopolies, trading restrictions, and the solicitation of subsidies or aid in exchange for political influence.