Heschel, often though of as an academic with a Hasidic background, was rather a Hasidic Rebbe with university training. This work, along with his other popular books (as opposed to the scholarly ones) is written in the form of a series of Hasidic discourses at a comfort level to the reader as if he were sitting with the Rebbe at the Third Sabbath Meal and absorbing his wisdom.
The central theme, the centrality of belief in and devotion to G-d, is often overlooked in contemporary Jewish literature; many veiled (and no so veiled) jibes of contemporary religious practice and life are meant to drive home the point that "it's about G-d and man", not about buildings, organizations or other agendas or programs.
Like the Kotzker Rebbe, Heschel's hero and spiritual father, Rabbi Dr. Heschel was able to cut through the gloss, fluff, and veneer to get to the root of man's belief in and relationship with G-d.