Contents * Preface Part One - A tutorial introduction * Introduction * Defining domain and control knowledge * How to interact with the user * A bird's eye view of the system Part Two - Using the KRL * Introduction to Prometheus * Informal introduction to KRL * Rules and logic * Rules and inference * Object-oriented programming Part Three - KRL Reference * Introduction * KRL metalanguage * Statements and program layout * Describing the domain level - frames * Describing the domain level - schemata * Describing the domain level - instances * Describing the domain level - relations * Describing the domain level - inheritance * The knowledge level - action rules * Describing the knowledge level - methods * Describing the control level - ATNS * Subcomponents of KRL - expressions * Subcomponents of KRL - paths and elements * Subcomponents of KRL - conditions * Subcomponents of KRL - commands * Linking to Prolog predicates * Matching * The syntax of tokens * The syntax of structures and lists * Errors Part Four - Programmer's Reference * Introduction * The run-time system References Index.