Yoga Nidra is a systematic approach to complete relaxation. Its roots are from India, and I am grateful to have studied under the tutelage of Sree Devi in Boulder, Colorado. It is incredibly restorative for all of our body's systems. Practicing for 30 minutes is said to be the equivalent of 2-3 hours of normal sleep. It is okay if you fall asleep! It simply means your body needed it. Enjoy!