This document provides guidelines for the life cycle management of systems and software, complementing the processes described in ISO/IEC/IEEE 15288 and ISO/IEC/IEEE 12207. This document: - addresses systems concepts and life cycle concepts, models, stages, processes, process application, key points of view, adaptation and use in various domains and by various disciplines; - establishes a common framework for describing life cycles, including their individual stages, for the management of projects to provide, or acquire either products or services; - defines the concept and terminology of a life cycle; - supports the use of the life cycle processes within an organization or a project. Organizations and projects can use these life cycle concepts when acquiring and supplying either products or services; - provides guidance on adapting a life cycle model and the content associated with a life cycle or a part of a life cycle; - describes the relationship between life cycles and their use in applying the processes in ISO/IEC/IEEE 15288 (systems aspects) and ISO/IEC/IEEE 12207 (software aspects); - shows the relationships of life cycle concepts to the hardware, human, services, process, procedure, facility and naturally occurring entity aspects of projects; and - describes how its concepts relate to detailed process standards, for example, in the areas of measurement, project management and risk management.