Although operational amplifiers were specifically designed for use in analogue computers, they soon became dominant in the world of linear electronics. Many of the early operational amplifiers still live on, and are in use today. On the other hand, there are now numerous "improved" devices, many of which offer tremendous advantages over the old "standards" in many practical applications. The first part of this handbook covers standard operational amplifiers based "building blocks" (integrator, precision, rectifier, function generator, amplifiers, etc.), and considers the ways in which modern devices can be used to give superior performance in each one. The second part describes a number of practical circuits that exploit modern operational amplifiers, such as high slow-rate, ultra low noise, and low input offset devices. The project include: low noise tape preamplifier; low noise RIAA preamplifier; audio power amplifiers; D.C. power controllers; opto-isolator audio link; audio millivolt meter; temperature monitor; low distortion audio signal generator; simple video fader; and many more.