Ramana Maharishi is one of India's most well known mystics in the west. He primarily taught in the holy city of Thiruvannamalai, which is known for its continuous lineage of enlightened masters. His teachings have been used by countless spiritual masters who followed, including modern western masters such as Eckhard Tolle. He gained fame in the west through a book written by Sir Paul Brunton called "A Search in Secret India"... his main method of working with his disciples was a simple query. The query is "Who am I"
In Depth: Who am I?
Video Biography: The Sage of Arunachala
Video Biography: Abide as the self
Book: A Search of Secret India - By Sir Paul Brunton