An Electronic Library System (ELS) is currently being developed for use in commercial aircraft. This system will supplement and eventually replace the conventional paper manuals with electronically stored data. Using advanced technologies of optical disk data storage, high resolution displays and sophisticated software, the ELS will provide a high degree of cockpit automation and added functionality for many avionics applications. Many airline operations will benefit from the cost savings that this system will offer, particularly maintenance operations. This paper will describe some proposed features of the ELS as well as the technology that will be used to implement it.