Enterprises are complex systems constantly seeking to adapt to the shifting environment. This book develops and validates a Framework for Enterprise Systems Engineering (ESE), which guides the engineering of an enterprise throughout its life cycle and highlights that an integrated enterprise is a system that creates value for its customers. The framework serves to management and engineering in their requirement for new model-based methods that support this enterprise need for adaptation and change. The framework intertwines a definition for ESE, setting its boundaries with respect to other disciplines; a classification scheme that remarks the different areas of study that ESE needs to address and breaks down an enterprise system into four elements, viewed through four system facets; each element-facet combination is subject to an engineering process to achieve a pre-specified performance. The book highlights the need for extensive research in ESE if it is to grow as a field and become the source of concepts, methodologies and tools to design, improve, and redesign enterprises of the 21st century.