This lab module offers brief, hands-on introductory coverage of DOS 3.3-5.0. Written in simple, straightforward language, the module adopts an accurate, readable, keystroke approach. A case study (used with all O'Leary lab modules) emphasizes concepts and provides realism, and there are review and practice exercises. The use of shaded boxes and commands results in an effective "action-result" methodology, and instructors can customize the text to fit their individual courses. Also available is a DOS 3.3-5.0 teaching materials set (0-07-911580-2).