During the studying BRE i found following survival guide for BRE.
Some excerpt form above link
Out of box the business rules engine (BRE ) is offered as either stand-alone .NET-compliant class library that includes a number of modules, support components, and tools or as component within your BizTalk solution enabling you to apply business rules to your processes (i.e. orchestrations). BRE implements the Rete algorithm , which is an efficient pattern matching algorithm for implementing production rule systems, and provides forward chaining execution. Forward chaining is one of the two main methods of reasoning when using inference rules (in artificial intelligence). This article will give you an overview of all relevant available resources regarding BRE to enable you to build robust solution with BRE.