Radio astronomy was founded by Grote Reber, an amateur radio operator. Radio itself was greatly advanced by Guglielmo Marconi, a young Italian man who started out by tinkering with a coherer and a spark coil as an amateur electrician. Pierre de Fermat was a highly influential mathematician whose primary vocation was law.
Many amateurs make valuable contributions in the field of computer programming through the open source movement. Amateur dramatics is the performance of plays or musical theater, often to high standards, but lacking the budgets of professional West End or Broadway performances. Astronomy, chemistry, history, linguistics, and the natural sciences are among the fields that have benefited from the activities of amateurs.