The current state of computer assisted instruction (CAI) in kindergarten through grade 12 is discussed. Four formats for CAI--drill, practice, tutorial, and simulation--are defined, and a set of criteria for distinguishing between effective and ineffective CAI are described. Comparisons are made between human and computer tutors. In response to teachers' concerns that CAI demonstrate superiority over textbooks, specific recommendations from the literature are provided for presenting text in a way that maximizes learner comprehension and for constantly monitoring learner readiness to absorb content information presented by computer programs. Suggestions are included for designing tutorial programs, with an emphasis on the importance of text presentation and proper specification of behavioral objectives. Finally, it is noted that simulation programs have the potential to develop higher levels of cognitive functioning. (3 references) (GL)