Tenai BeNissuin Uveget (Conditionality in Marriage and Divorce) is a 20th-century Hebrew work by Rabbi Dr. Eliezer Berkovits that explores the concepts of conditional marriage and retroactive annulment of marriage. Berkovits was responding to the problem of agunot, which he saw as particularly prevalent in his generation. As he describes it, many agunot were choosing to remarry in violation of Jewish law, thereby rendering their future children mamzerim. Berkovits felt a need to explore potential halakhic solutions and hoped others would further develop and implement them. The work received a letter of approbation from Berkovits’s teacher, Rabbi Yechiel Yaakov Weinberg, but Berkovits faced much opposition from other Orthodox rabbinic leaders in his attempt to publish the book and in its aftermath.