Yogananda's 'grandfather guru'
the Indian mystic tradition involves lineage -- lineages of knowledge that is passed down from guru to student, who then becomes a guru to the next wave of students, and so on. this is called Guru Parampara (guru lineage) and insures that the secret divine knowledge, things that can't be written down and can hardly be spoken of, are passed down, protected from abuse and misunderstanding, and kept alive to serve the planet in the hands of the saints.
Lahiri Mahasaya was an unassuming Indian railroad employee for all of his life. he was also a MAJOR supernatural saint, a great siddha. his own wife didn't even know his abilities until one night she was awakened in their bedroom by the sight of her husband of decades, levitating near the ceiling, surrounded by a group of angels!