This book presents a systematic, easy-to-apply methodology for creating effective requirements. The authors present practical solutions for the full requirements lifecycle: gathering, analysis, specification, verification, and maintenance. Working in the context of the Unified Process, they cover process flows, present detailed diagrams, and offer insights that draw on their extraordinary mission-critical project experience, which ranges from the floor of the New York Stock Exchange to the U.S. Air Force's most advanced Command and Control Systems.