Nisargadatta Maharaj lived an unremarkable life as a small businessman in the Khetwadi neighbourhood of Mumbai before encountering his teacher Siddharameshwar Maharaj in 1933. Within three years he was awakened. He continued running his bidi-cigarette shop until late in life, receiving visitors in the small upper room of his apartment where the conversations later collected as I Am That were recorded.
His teaching is uncompromisingly direct. The world is not what you take it to be. The body is not what you take it to be. The person is a temporary appearance in awareness, not the awareness itself. Investigate the I-am, find what is prior to it, and the question of liberation no longer arises.