Sefer Tanya is a foundational work of Chabad Chassidut, authored by Rabbi Shneur Zalman of Liadi, the founder of the Chabad movement. It is also known as "Likkutei Amarim" (ליקוטי אמרים). First published in 1797, Tanya explores the complexities of the human soul, the concept of the divine, and the spiritual dynamics within every individual. Key Themes and Contents of Sefer Tanya: Dual Soul Concept: Tanya introduces the idea that every Jew possesses two souls: an animal soul (nefesh habehamit), which is the source of self-centered desires, and a divine soul (nefesh haElokit), which seeks closeness to Hashem and is driven by selflessness and spirituality. Spiritual Struggle: A significant portion of Tanya discusses the inner struggle between these two souls, aligning closely with the concepts of Yetzer Hara and Yetzer Hatov. It provides practical advice on how to navigate this conflict to lead a life aligned with Torah values. Achieving Unity with Hashem: Tanya delves into the ways through which a person can achieve unity with Hashem, primarily through Torah study and mitzvah observance, emphasizing that these spiritual activities connect the divine soul with its source. Tzimtzum and Divine Omnipresence: The text also addresses complex Kabbalistic concepts like Tzimtzum (the self-constriction of the Divine to allow for the existence of a seemingly independent reality) and explains how Hashem's presence permeates all existence, albeit in a concealed manner. Sefer Tanya is considered both a theological and practical guide, offering insights into spiritual psychology and providing guidance on personal growth and refinement. It is central to the study and practice of Chabad Chassidim and has a significant influence on Jewish thought and practice beyond Chabad.