Rabbi Eliezer Yehuda Waldenberg (b.1917), known as theTzitz Eliezer, after his monumental halachic treatise of that name, is a judge on the Supreme Rabbinical Court in Jerusalem, and a leading authority on medical halacha. Rabbi Waldenberg has been one of the leading authorities when it comes to questions of medical halacha ranging from the permissibility or non-permissiblity of smoking to cosmetic surgeries to the boundaries of pekuach nefesh (the concept that most religious laws can be violated in order to save a person's life) when it comes to medicine, in particular those areas of medicine that are experimental and push the envelope. He has also been a major authority on non-medical issues both within and outside of Haredi circles, with his opinions being valued by Orthodox and Conservative rabbis alike. His major work, the Tzitz Eliezer, an encyclopedic treatise on halachic questions of vast range, is viewed as one of the great achievements of halachic scholarship of the last century. However, certain rulings of Rabbi Waldenberg's have been especially controversial, especially his minority opinion that in some limited cases pekuach nefesh allows sex reassignemnt surgery (SRS) for transsexuals and his view that such surgery can in some cases change a person's halachic sex. Indeed, these opinions have been so controversial that even many of his students have denied that he ever issued them, although they are contained in the Tzitz Eliezer. The major halchic treatise of Rabbi Eliezer Waldenberg, the Tzitz Eliezer covers a wide breadth of halacha clarifying both the issues of medical halacha in which Rabbi Waldenberg was considered unparalleled as well as more common halachic questions surrounding everything from Shabbos and kashrut to questions of theology. ...