Mikao Usui (臼井甕男, 15 August 1865 – 9 March 1926, commonly Usui Mikao in Japanese) was the father of a form of spiritual practice known as Reiki used as an alternative therapy for the treatment of physical, emotional, and mental diseases. According to the inscription on his memorial stone, Usui taught Reiki to over 2,000 people during his lifetime.

As an adult, it is believed that he traveled to several Western countries, including the Americas, Europe, and China as a part of his continued study. His studies included history, medicine, Buddhism, Christianity, psychology, and Taoism.

It is believed that the aim of Usui’s teachings was to provide a method for students to achieve connection with the “universal life force” energy that would help them in their self-development. What sets Usui’s teachings apart from other hands-on healing methods is his use of reiju or attunement to remind students of their spiritual connection. It seems that all students of Usui received five principles to live by and those with a further interest in the teachings became dedicated students. People began coming to Usui Mikao possibly for different purposes – some for healing and others for the spiritual teachings.