Template:Infobox Person Rabbi Moshe Feinstein (March 3, 1895–March 23, 1986) was a Lithuanian Orthodox rabbi, scholar and Posek, who was world renowned for his expertise in halakha and was the de facto supreme rabbinic authority for Orthodox Jewry of North America. In the Orthodox world, it is universal to refer to him simply as "Reb Moshe."
Rabbi Feinstein was born, according to the Hebrew calendar, on the 7th day of Adar, 5655 (traditionally the date of birth of the Biblical Moshe) in Uzda, near Minsk, Belarus, then part of the Russian empire.
The son of Rabbi David Feinstein, rabbi of Uzdan, Moshe studied with his father and also in the yeshivas of Slutsk, Shklov and Amstislav, before being appointed rabbi of Lubań where he served for sixteen years. Under increasing pressure from the Soviet regime, he moved with his family to New York City in 1936 where he lived for the rest of his life.
Settling on the Lower East Side, he became the rosh yeshiva of Mesivtha Tifereth Jerusalem. He later established a branch of the yeshiva in Staten Island, New York, now headed by his son Rabbi Reuven Feinstein. Moshe's son Rabbi David Feinstein heads the Manhattan branch.
He was president of the Union of Orthodox Rabbis of the United States and Canada and chaired the Moetzes Gedolei HaTorah of Agudath Israel of America from the 1960's until his death. Rabbi Feinstein also took an active leadership role in Israel’s Chinuch Atzmai.
Rabbi Yaakov Yisrael Kanievsky ("the Steipler"), Rabbi Yonasan Steif, Rabbi Elyah Lopian, Rabbi Aharon Kotler, Rabbi Yaakov Kamenetsky and Rabbi Yosef Shalom Elyashiv all revered Rabbi Feinstein and declared him to be the Godol Hador (greatest Torah sage of the generation), although several of them were far older than he. He was universally recognized as the preeminent sage of his generation, and people from around the world called upon him to answer their most complicated halachic questions.
Owing to his prominence as a decisor of Jewish law, Rabbi Feinstein issued a number of innovative or controversial decisions. He ruled as an independent posek and through beit din (Jewish rabbinic court) judgments. Soon after arriving in the United States, he established a reputation for handling business and labor disputes. For instance, he wrote about strikes, seniority, and fair competition. Later, he served as the chief halakhic authority for the Association of Orthodox Jewish Scientists, which suited his growing involvement with medical ethics cases. In the medical arena, he fiercely opposed the early, unsuccessful heart transplants and, over time, he seems to have shifted toward acceptance of brain death criteria. On such matters, he consulted with various scientific experts, including his son-in-law Moshe Dovid Tendler.
As a leader of American Orthodoxy, moreover, Rabbi Feinstein issued opinions that clearly distanced his community from Conservative Judaism and Reform. Nevertheless, he faced intense opposition within Orthodoxy on several controversial decisions, such as rulings on artificial insemination and eruv. Indeed, on the former, Rabbi Feinstein may be read as having reversed or seriously qualified his position. In the case of his position not to prohibit cigarette smoking, Orthodox rabbinic authorities overruled, in effect, his decision after his death. He made noteworthy decisions on the following topics:
- Artificial insemination from a non-Jewish donor (EH I:10,71, II:11, IV:32.5) 
- Cosmetic surgery (HM II:66)
- Bat Mitzvah for girls (OH I:104 (1956), OH II:97 (1959), OH IV:36)
- Brain death as an indication of death under Jewish law (YD IV:54)
- Cheating for the N.Y. Regents exams (HM II:30)
- Classical music in religious settings (YD II:111)
- Commemorating the Holocaust, Yom ha-Shoah (YD IV:57.11)
- Conservative Judaism, including its clergy and schools (e.g., YD II:106-107)
- Donating blood for pay (HM I:103)
- Education of girls (e.g., YD II:109, YD II:113 YD III:87.2)
- End-of-life medical care
- Eruv projects in New York City
- Financial ethics (HM II:29)) 
- Hazardous medical operations
- Heart transplantation (YD 2:174.3)
- Labor union and related employment privileges (e.g., HM I:59)
- Mehitza (esp. OH I:39) 
- Psychiatric care (YD II:57)
- Separation of Siamese twins 
- Shaking hands between men and women (OH I:113, EH I:56)
- Smoking marijuana (YD III:35)
- Tay-Sachs fetus abortion, esp. in debate with Rabbi Eliezer Waldenberg 
- Smoking cigarettes 
- Veal raised in factory conditions (HM I:103)
Note: Responsa in Igrot Moshe are cited in parentheses
Rabbi Feinstein died on the 23 March 1986 (13th of Adar II, 5746 on the Hebrew calendar). It has been pointed out that the 5746th verse in the Torah reads, "And it came to pass after Moshe had finished writing down the words of this Torah in a book to the very end." (Deuteronomy 31:24). This is taken by some as a fitting epitaph for him.
At the time he was regarded as Orthodoxy's foremost rabbinic scholar and halachic decisor. His funeral in Israel was said to be the largest among Jews since the Mishnaic era, with an estimated attendance of 300,000 people. Among the eulogizers in America were Rabbis Yaakov Yitzchak Ruderman, David Lipschutz, Shraga Moshe Kalmanowitz, Nissan Alpert, Moshe David Tendler, Michel Barenbaum and Mordechai Tendler. The Satmar Rebbe and Rabbi Feinstein's son Rabbi Reuven also spoke.
In Israel, Rabbis Elazar Menachem Shach, Dovid Povarsky, Yitzchak Yaakov Weiss, Yehuda Tzadkah, Rabbi Feinstein's son Reuven and Rabbi Feinsteins's nephew Rabbi Michel Feinstein, all tearfully expressed grief over what they termed a massive loss to the generation.
Rabbi Feinstein was held in such great esteem that Rabbi Shlomo Zalman Auerbach, who was himself regarded as a Torah giant, Talmid Chacham and Posek, refused to eulogize him, saying "Who am I to eulogize him? I studied his sefarim; I was his talmid (student)."
Rabbi Feinstein invested much time molding some of his select students to become leaders in Rabbinics and Halacha. Those students, over the years, spent countless hours a day serving as apprentices to their great Rabbi. Most are considered authorities in many areas of practical Halacha and Rabbinic and Talmudic academics. Some of those students are:
- Rabbi Nissan Alpert, (New York, NY)
- Rabbi Avrohom Blumenkrantz, (Far Rockaway, NY)
- Rabbi Elimelech Bluth, (Brooklyn, NY)
- Rabbi David Feinstein, (New York), his son and foremost disciple
- Rabbi Aaron Felder, (Philadelphia, PA)
- Rabbi Chaim Ganzsweig, (Los Angeles, CA and New York)
- Rabbi Efraim Greenblatt, (Memphis, TN)
- Dayan Gershon Lopian, (Edgware)
- Rabbi Hershel Reichman, (New York, NY)
- Rabbi Joseph Rottenberg, (Baltimore, MD)
- Rabbi Mordechai Tendler, (New Hempstead, NY)
- Rabbi Moshe David Tendler, (New York, NY)
- Rabbi Chaim Ozer Chait, (Richmond, VA)
Rabbi Feinstein's greatest renown stemmed from a lifetime of responding to halachic queries posed by Jews in America and worldwide. He wrote about two thousand responsa on a huge range of issues that affect Jewish practice in the modern era. Some responsa may be found in his Talmudic commentary (Dibros Moshe), some circulate informally, and 1,883 responsa were published in Igrot Moshe. Among Rabbi Feinstein's works:
- Igros Moshe; (Epistles of Moshe), a classic eight-volume work of Halachic responsa.
- Dibros Moshe (Moshe's Words), an eleven-volume work of Talmudic novellae.
- Darash Moshe (Moshe Expounds, a reference to Leviticus 10:16), novellae on the Torah (published posthumously).
Some of Rabbi Feinstein's early works, including a commentary on the Talmud Yerushalmi, were destroyed by the Soviet authorities.
- Template:Cite book
- Ellenson, David. "Two Responsa of Rabbi Moshe Feinstein." Chronicle of Hebrew Union College, Volume LII, Nos. 1 and 2, Fall 2000-2001.
- Template:Cite book
- Rabbi Shimon Finkelman, Rabbi Nosson Scherman. Reb Moshe: The Life and Ideals of HaGaon Rabbi Moshe Feinstein. Brooklyn, NY: ArtScroll Mesorah, 1986. ISBN 0-89906-480-9.
- Template:Cite book
- Template:Cite paper
- Template:Cite web
- _________. "Jewish education for women: Rabbi Moshe Feinstein's map of America." American Jewish history, 1995
- Rackman, Emanuel. "Halachic progress: Rabbi Moshe Feinstein's Igrot Moshe on Even ha-Ezer" in Judaism 12 (1964), 365-373
- Robinson, Ira. "Because of our many sins: The contemporary Jewish world as reflected in the responsa of Moses Feinstein" 2001
- Rosner, Fred. "Rabbi Moshe Feinstein's Influence on Medical Halacha" Journal of Halacha and Contemporary Society. No. XX, 1990
- __________. Rabbi Moshe Feinstein on the treatment of the terminally ill." Judaism. Spring 37(2):188-98. 1988
- Warshofsky, Mark E. "Responsa and the Art of Writing: Three Examples from the Teshuvot of Rabbi Moshe Feinstein," in An American Rabbinate: A Festschrift for Walter Jacob Pittsburgh, Rodef Shalom Press, 2001 (Download in PDF format)
- Igros Moshe is available for free online at hebrewbooks.org. Type אגרות משה into the sefer box for pdfs of all eight volumes.
- For example, see Roth, Joel. The Halakhic Process: A Systematic Analysis, JTS: 1986, pp.71ff. Robinson (2001).
- Cohen, A. in JHCS
- Halperin (2006)
- See esp. Joseph (1995)
- Feinstein & Tendler (1996)
- Roth (1989), op. cit. on YD 139.
- Joseph (1995)
- Tzedakah and Tzedek: Halachic & Ethical Financial Requirements Pertaining to Charitable Organizations by Daniel Feldman 
- Baruch Litvin, The Sanctity of the Synagogue, 1962
- Tendler excerpt on Jlaw.com
- E.g., see Sinclair, Daniel. Jewish Biomedical Law 2004
- See RCA decision and, earlier, RCA Roundtable. (Statement by progressive Orthodox Rabbis Saul Berman, Reuven Bulka, Daniel Landes and Jeffrey Woolf.) “Proposal on smoking” (unpublished) July 1991.