Book excerpt: Nefesh HaTzimtzum provides the single most comprehensive and accessible presentation of the teachings and worldview of the Vilna Gaon's primary student, Rabbi Chaim Volozhin. It is focused on Rabbi Chaim's magnum opus, Nefesh HaChaim, a work that has lain in almost total obscurity for nearly two centuries due to its deep Kabbalistic subject matter. Nefesh HaTzimtzum opens up the real depth of the ideas presented in Nefesh HaChaim together with all of Rabbi Chaim's related writings, making them accessible to the public for the first time in any language. In addition to the complete English translation of Nefesh HaChaim, Nefesh HaTzimtzum includes the full Hebrew text of Nefesh HaChaim and many other writings by Rabbi Chaim (with correspondingly hyperlinked English and Hebrew texts), along with in-depth explanations, an informative historical overview, an easily consumable innovative presentation layout and a full index. After centuries of confusion, extensive clarification is provided of the central Kabbalistic concept of Tzimtzum, or the secret of how an infinite God occupies a finite world. Most importantly, it unequivocally demonstrates that the key Kabbalists, including the Vilna Gaon, Rabbi Chaim Volozhin and the Baal HaTanya, all unanimously agreed on the underlying principles of the concept of Tzimtzum and that contrary to widespread historical misunderstanding, there was no fundamental dispute about the philosophical principles of Judaism between the Hasidim and the Mitnagdim. Based on this Nefesh HaTzimtzum shows that both Nefesh HaChaim and Sefer HaTanya present the same methodology for serving God which is rooted in their identical understanding of the concept of Tzimtzum. Nefesh HaTzimtzum is published in two volumes which are sold separately. This volume contains the complete Hebrew text of Nefesh HaChaim which is brought to life by an illuminating translation and incisive commentary. It additionally provides extensive translated source material necessary to properly understand the basic text. The text is further complemented by an informative introduction which includes a historical overview.