Intelligent Tutor Systems aim to individualize instruction through Intelligent Computer Aided Instruction (ICAI) by modeling both domain knowledge and student models. They consist of components like ACT*, which represents skills as goal-directed rules. Building an effective tutor requires studying common student errors, observing tutors, and constructing models of how students solve problems. Ms. Lindquist's architecture represents the student's competence through production rules and implements the tutor model with additional production rules to choose pedagogical strategies based on the student's diagnosis. Principles for tutor design include representing student knowledge, communicating problem-solving goals and structures, providing context-specific instruction, and adjusting instruction granularity based on learning. However, Intelligent Tutor Systems