This chapter introduces the features of the Keysight 8163B Lightwave Multimeter, the Keysight 8164B Lightwave Measurement System, and the Keysight 8166B Lightwave Multichannel System. In general, if not specifically mentioned, the information in this User Guide also applies to the previous generation of 8163A, 8164A and 8166A. Here you will find a quick description of the instrument, how to use the user interface and how to perform a simple sample session.