Yehoshua Yeshaya Neuwirth (Hebrew: יהושע ישעיה נויברט‎) (1927 {also 1935} - 2013) was an eminent Orthodox Jewish rabbi and posek (halakhicauthority) in Jerusalem, Israel. He was one of the primary and most renowned students of Rabbi Shlomo Zalman Auerbach and the author of a two-volume Hebrew language treatise, Shemirat Shabbat Kehilchatah (Hebrew: שמירת שבת כהלכתה‎)— translated into English asShemirath Shabbath: A practical guide to the observance of Shabbath — a compendium of the laws of Shabbat which is viewed by many as an authoritative work regarding these laws. He was also the rosh yeshiva of the Prei Shmuel yeshiva ketana and Chochmas Shlomo yeshiva gedola in Jerusalem. He lived in the Bayit Vegan neighborhood of Jerusalem.

Rabbi Neuwirth was a leading disciple of Rabbi Shlomo Zalman Auerbach. While Rabbi Auerbach issued most of his halachic rulings orally, Rabbi Neuwirth publicized many of his teacher's rulings on Hilkhot Shabbat (Shabbat laws) in his book, first published in Hebrew in 1965. Additionally, 8 of the 32 chapters of this book were devoted to Rabbi Auerbach's rulings on medical halacha.

With the publication of his book, Rabbi Neuwirth introduced a new format for studying the laws of Shabbat. Previous texts for the general public were organized according to the presentation in the Shulchan Aruch. Rabbi Neuwirth organized his book by topic and provided a clear index; he also embellished the presentation with thousands of references and comments. Feldheim Publishers published the first volume of the English-language translation in 1984; volumes 2-4 appeared in 1989, 1997, and 2001, respectively, and the current three-volume boxed set was issued in 2002.

Rabbi Neuwirth (left) with his Rav, Rabbi Shlomo Zalman Auerbach.

Widely regarded as an expert on Jewish law and medical ethics, Rabbi Neuwirth's opinion was frequently cited on issues such asgenetic screening, brain death, euthanasia, and AIDS, as well as laws for physicians on Shabbat. He was also a consultant for the Zomet Institute, providing the halakhic authorization for innovations such as the Shabbat lamp and electric wheelchairs on Shabbat.

Bibliography

• Chinukh Ha-Banim Le-Mitzvos Ve-Dinei Katan (Educating Children for Mitzvos and Laws of Youth) (Hebrew)
• The Halachoth of Educating Children
• Kitzur Dinei Shmita Karkaot (Concise Laws of Shmita)
• Shemirat Shabbat Kechilchatah (Hebrew), 1965 — translated into English as Shemirath Shabbath: A guide to the practical observance of Shabbath[