This book is about understanding technology using the perspective of systems. It addresses the need for an accessible approach to understanding the broad range of technological devices and systems that create the modern world. Understanding technological systems offers an introduction to engineering and technology centered on the underlying structure common to all technological objects. This framework views technological systems as created using components to provide specific capabilities or functions. Components contributing well-defined functions interact with other components to create systems. Major topics include the concepts of technological function and the embedding of functional capabilities in physical components, the hierarchical nature of systems, and the clustering of related systems into technological domains. The book fills the gap between engineering science and engineering design.