R. Shneur Zalman of Liady (1745–1813), the founder of Habad Hasidim was according to family traditions born in Liozna, Belorussia, on the 18th of Elul. After his marriage in 1760 he devoted himself to Torah study. Concluding that he knew "a little about learning, but nothing about prayer" in 1764 he decided to learn about Hasidism from R. Dov Baer the Maggid of Mezhirech, leader of the Hasidic movement. In Mezhirech he became one of the inner circle of the Maggid's pupils. Although he was one of the youngest pupils, the Maggid had a high opinion of him, and in 1770 delegated to him the task of composing a new and up-to-date Shulhan Arukh. R. Shneur Zalman worked on this book for many years, but published only small parts of it. About one-third was printed posthumously (the rest had been destroyed by fire) and is known as the "Shulhan Arukh of the Rav" (1814). Though not a hasidic work, it represents - as the Maggid had intended - a great halakhic achievement. It evidences R. Shneur Zalman's superb Hebrew style, his ability to provide lucid explanation, and profundity without complexity. It became an authoritative halakhic source among observant Jews.

שני שערים. השער הראשון קצר: "סדר תפלה עם תורה אור ועם שערי תפלה...". שער זה נדפס בדיו כחולה ואדומה. נוסח חב"ד. חלק א: תפילות לכל השנה. חלק ב: כולל כל הענינים שלא היו בסדורים הראשונים... כמו... קריאות והפטרות לשלש רגלים [ועוד]... סליחות... סדר וידוי לשכיב מרע... דיני צדוק הדין... מה שאומרים בבית האבל...שערי תפלה...דרך החיים... ונתיב החיים... דיני קריאת התורה, מלוקטים מן שער אפרים של... ר' אפרים זלמן מרגליות... .