Rachel Elior's The Paradoxical Ascent to God: The Kabbalistic Theosophy of Habad Hasidism, is a scholarly treatment of early Habad thought on the nature of God, and its expression in religious practice.
The title reveals much of thesis. Merging with God, devekut, is strongly stressed in Habad, often in linear language. One ascends to God, moves up to God; but in reality, God is everywhere in Habad theology, so there is no up, no down.
The struggle between God as transcendent and imminent, as separate from the world and as permeating the world, guides Elior's study. She explores how early Habad struggled with its own unique conception of a God as both present and absent from the world.
On the negative side, Elior repeats herself a great deal. This book would have made an excellent long paper, but in book form, it often covers the same or similar ground. She also tends to treat the material a-historically, not giving enough context for when and where the text she is studying was produced and read.
At times this gives the book the feel of a high end manual on Habad practice and thought, and not an historical study.