R' Levi Yitzchok of Berdichtov was one of the main discples of the Maggid of Mezeritch who was the successor to the Baal Shem Tov. He was the famous Melitz Yosher, a passionate believer in the inherent goodness of human beings. He always found a way to give another Jew the benefit of the doubt.
His method of prayer can be described only as ecstasy. His work, Kedushas Levi, from which the above idea was drawn, is an essential element in any Chassidic library.