Reiki is a technique that is passed on from teacher to student over and over. If one has Reiki, than she/he will be part of a succession of teachers leading back to the founder of the system of Reiki one is practicing. In the case of Usui Reiki, the lineage would lead back to Dr. Mikao Usui. I personally have had multiple teachers, to learn more and varied Reiki techniques. Some of these are not listed here as I don't have details of their lineage.