The active noise-reducing headset is probably the most successful application of active control of sound. This presentation provides a technical review of the active noise-reducing headset, giving examples of applications where it is most successfully used. The principles of passive noise attenuation are presented, after which active attenuation is introduced showing how the two complement the attenuation performance. Both analogue and digital implementations of the headset control system are described, including combination of analogue and digital controllers into a single system. The paper concludes with a view into the future where new technologies open possibilities for improving the headset performance in more challenging environments.