This textbook introduces Instrumentation devices in a way sufficiently complete so that the reader acquires an ability to make meaningful measurement of three important process parameters - temperature, pressure, flow - as well as other mechanical and chemical parameters. The book offers a comprehensive coverage of instrumentation and its practical implementation with an excellent balance of theoretical concepts and engineering practice. Any instrumentation system is incomplete without signal conditioning circuits and for this purpose one full chapter is devoted to various signal conditioning circuits. The book is designed for a one-semester course in Industrial Instrumentation or Instrumentation Devices.