MUSE is a method developed specifically to extend the scope of human factors contributions beyond late evaluation and thus increase their effectivness and uptake. This is accomplished by making inputs more explicit, early and continuous throughout the system development process. Since MUSE's scope spans user requirements to user interface design, it supports active human factors involvement in both design specification and evaluation. MUSE defines how, what and when particular human factor concerns should be addressed. It also specifies the procedures, notations, and documentation involved. This book will be essential reading for all involved with systems development, whether from the HCI or software engineering communities, and can be used as well for course accompaniment.