The Automated Mathematician (AM) is one of the earliest successful discovery systems. It was created by Doug Lenat in Lisp, and in 1977 led to Lenat being awarded the IJCAI Computers and Thought Award.
A sequal to Automated Mathematician, it consists of heuristics, i.e. rules of thumb, including heuristics describing how to use and change its heuristics. It was applied to a number of domains with surprising success. See Chapter 5 of Eric Drexler's Engines of Creation for more about Eurisko.
Douglas Lenat programmed Automated Mathematician (AM), a program to rediscover number theory by itself.
See also: What is the meaning of Organization, System, Artificial intelligence, Knowledge, Heuristics?