The most fascinating, intriguing and philosophically engaging book of the Tanakh (if we are allowed to indulge in ratings) is undoubtedly the first one -- Bereshit, or Genesis. It tackles questions of creation and destiny, society and government, as well as the different facets of human behavior, sibling rivalry, envy and miscommunication.
Etshalom's book cannot replace a study partner; no single book can do that. I'm sure that Etshalom would agree with me on this point, but his book is not meant to do that. Etshalom's book is meant as a sort of introductory field guide to Torah.