Expert systems are comprised of methods, procedures, and algorithms that are used interchangeably. There are many methods for processing information which claim to be artificially intelligent. Most likely, the largest single grouping of such methods is contained in a set defined as being “expert systems”. Again, many have defined expert systems as being many different things; here an expert system will be, in the context of computer science, a system which contains one or all of tools, rules, calculations, and logic to manipulate large amounts of information specific to a domain which typically human experts are used to make decisions in. Examples include medical expert systems, mineral exploration systems, and intelligent stock trading systems. Each of these is designed to work in a specific field where usually a human expert is necessary. In most cases, an expert system will be used as a partner to assist rather than replace the expert, especially in the case of medical expert systems.