Here it is--a collection of Forrest Mims's classic work from the original Popular Electronics magazine! Using commonly available components and remarkable ingenuity, Forrest shows you how to build and experiment with circuits like these: analog computers color organs digital phase-locked loops frequency-to-voltage and voltage-to-frequency converters interval timers LED oscilloscopes light wave communicators magnetic field sensors optoelectronics pseudorandom number generators tone sequencers and much, much, more!