The fourth volume of Meḥqerei Talmud published on behalf of the Department of Talmud at the Hebrew University of Jerusalem is dedicated to Professor David Rosenthal on the occasion of his eightieth jubilee. Professor David Rosenthal is one of the leading researchers of the Mishnah and the Talmud , and his research also encompasses diverse bordering fields. In his bright studies and his captivating teaching, he produced countless brilliant and pulsating innovations. Some of them, which constitute the core of Talmud research, changed research concepts and set the research agenda with basic questions. Prof. Rosenthal, together with his colleagues, edited the series Meḥqerei Talmud from its inception in 1959. The articles in the collection are the fruit of the research of his colleagues and students, in his main fields of activity and in bordering fields.