It is interesting that the general view of rule-based systems as "rule-based expert systems" begs the question: is there such a thing as non-rule-based expert systems or rule-based non-expert systems ? I think the answer is yes.

For instance, the KBSC site mentions that the company "deals mostly with rulebased systems in the business world where they are sometimes referred to as Business Rule Management Systems, BRMS". In other words, rule-based non-expert systems, also know as business rules.

Oddly, this may be one of the best definitions of "rule-base system". It's when you do ....

Conventionally, rule-based systems are defined as or are closely associated with expert systems. But the usually ever-reliable Wikipedia mentions them only in the context of expert systems and that only in passing.  THe central definition of expert system is:

 From th RuleML site:

The participants of the RuleML Initiative constitute an open network of individuals and groups from both industry and academia. ... Our main objective is to provide a basis for an integrated rule-markup approach that will be beneficial to all involved and to the rule community at large.

Updated Sept 7 2008: Found new link to Diane Cook lecture notes ...

Rule Based Systems and Artificial Intelligence

One of the better and more accessible rule-based system links is the student notes for a course on AI given by Jocelyn Paine in 1996.

The Jocelyn Paine definition of rule-based systems:

Tons of interesting aritcles at the System and Software Engineering lab (SSEL) ... many need a bit of googling to find them all.

Many links can be found on the VUB Publications page. Also check out the thesises ... thesii ? ...

The general basis of many of the articles is Aspect Oriented Programming, but the focus at VUB is business rules and rule-based systems.