Alfred Nobel, a Swedish inventor contributed most of his vast fortune in a trust as a fund from which annual prizes could be awarded to individuals and organizations who had achieved the greatest benefit to humanity in a particular year. Originally, there were six classifications for outstanding contributions designated in Nobel's will including chemistry, physics, medicine, literature, and international peace. The prizes are administrated by the Nobel Foundation in Stockholm. In 1969, a prize for economics endowed by the Central Bank of Sweden was added. Candidates for the prizes must be nominated in writing by qualified authority in the field of competition. Recipients are selected by their respective institutions. The prizes are usually presented in Stockholm on December 10, with the King of Sweden officiating, an appropriate tribute to Alfred Nobel on the anniversary of his death. Each one includes a gold medal, a diploma, and a cash award of about a million dollars. What does this passage mainly discuss?