With Rabbi Schnuer Zalman of Liadi's commentary on the daily prayers as a springboard, his son, Rabbi DovBer of Lubavitch, the Mittler Rebbe, delves into the spiritual worlds affected by prayer and the nature of the soul in the act of prayer. This work, which was first published by Rabbi DovBer, has benefited from a crisp typesetting and careful editing to weed out textual inaccuracies.