A binaural beat isn’t so much a beat as a sensation you think you hear when your brain tries to synthesize two tones of slightly different frequency playing in opposite ears. The effect can be calming and meditative, and is thought to enhance focus—and deep sleep. But at the end of the day, if it feels good, it’s working. Consider this playlist a useful introduction to one of the more interesting emergent phenomena in healing sounds. Our editors recalibrate selections here regularly, so if something in particular clicks, add it to your library.