Prizes for the encouragement of men and women who work for the interests of humanity, established by the will of Alfred B. Nobel (1833-1896), the Swedish inventor of dynamite, who left his entire estate for this purpose. They are awarded yearly for what is regarded as the most important work during the year in physics, chemistry, medicine or physiology, idealistic literature, and service in the interest of peace. The prizes, averaging $40,000 each, were first awarded in 1901. The monetary value of the awards have increased each year, to near one million U. S. dollars by the end of the 20th century.