This paper presents a series of lecture notes prepared by a group of researchers at the NASA Ames Research Center. The aim of the lecture series is to provide an overview of how aircraft engines work and fail, with the overall purpose of familiarizing the researchers with the general issues. The lectures provide a good introduction to the general topic, and will serve as a starting point for a group of researchers interested in applying their expertise to aircraft engine health monitoring for condition-based maintenance. The paper provides a summary of these lectures, to encourage other researchers to conduct similar reading and lecture series. INTRODUCTION A group of researchers at the NASA Ames Research Center has started working on engine health monitoring (EHM). The purpose of the basic research Copyright 1999 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. program is to explore ways to use Engine Monitoring Systems to reduce the cost of engine maintenance and to increase safety. The solution the group is aiming for is robust and reliable engine health monitoring and diagnostics systems with improved detection and diagnosis capabilities. The group has a combined expertise in condition monitoring and diagnostics, aeronautical engineering, mechanical engineering, software engineering, and helicopter dynamics and monitoring. To help with the advance of the engine health monitoring project, the authors have organized a set of engine lectures. The audience is the group of researchers interested in engines. The purpose of the lecture series is to join our expertise in order to understand how aircraft engines work and what failure modes are of concern to the users and designers. In this paper, we summarize the format and content of these lectures, with the purpose of encouraging researchers to conduct similar lecture series in their aircraft engine research. Based on verbal feedback, we know that the lecture series have been very beneficial to all who are involved, and we encourage the readers to use the approach proposed in this paper for their purposes.