This book starts with processing functions and signals and their properties, and then analyses the features of many electronic systems. It studies building blocks like transistors and passive components at a functional level, with special attention on their practical limitations and associated realization problems. This study encourages learning at increasing levels of detail while it is covered in both analog and digital solutions. The validity of the theory described is proved in numerous examples, simulations, exercises, and verification results. A balanced amount of information on computer aided design (CAD) is given in the introductory chapter. This enables a profitable use of CAD for design experiments, without getting the reader lost in unnecessary details. Mathematics and signal processing theory is kept to a minimum.