This book provides a basis by which instruments and transducers can be selected, assembled and integrated with a computer to measure and control physical processes in an accurate and predictable manner. It consists of two parts, the first of which lays the theoretical foundation for the second. First the Fourier analysis of signals are summarized. Then, from a systems point of view, the following chapters introduce the important aspects of filters, amplifiers and analog-to-digital converters. The second half of the book first discusses in depth the importance of the timing of the computer with its instruments, transducers and actuators. It then summarizes the physical and functional aspects of transducers and actuators and gives numerous detailed examples of how they can be integrated into computer controlled experiments and processes.