This book presents the methodology of complex activity with a set of interconnected mathematical models that describe the processes of technology design, adoption and use. It first discusses the technology of complex activity and its general models. The second chapter then introduces models of the processes of technology design and adoption, while Chapter 3 focuses on technology management models are presented in. Lastly, Chapter 4 examines analytical complexity and errors in solving technology design/optimization problems. This book is intended for experts and researchers interested in the general principles of activity organization and control of complex organizational and technical systems.