Mesillat Yesharim

Mesillat Yesharim ("The Path of the Upright") was written by Rabbi Moshe Chaim Luzzatto, the Ramchal, and printed in Amsterdam in 1740. It follows the ladder of Rabbi Pinchas ben Yair in the Talmud (Avodah Zarah 20b): Torah leads to watchfulness, watchfulness to zeal, zeal to cleanliness, cleanliness to separation, separation to purity, purity to piety, piety to humility, humility to the fear of sin, and the fear of sin to holiness. Each chapter explains one rung, what it is, how to acquire it and what stands in its way, starting from the principle that "the foundation of piety and the root of perfect service is for a person to make clear to himself what his duty is in his world".

Written in clear and simple Hebrew, the book became the most widely studied work of Jewish ethics. Rabbi Israel Salanter made it a core text of the Mussar movement in the 19th century, and it is still learned daily in yeshivot. The Vilna Gaon is said to have praised it highly. It is printed in many editions and translations, and stands alongside Bachya ibn Paquda's Duties of the Heart.