Isaac Klein (1905-1979). During World War II Rabbi Klein served as a chaplain in the U.S. Army, and later served as a Conservative rabbi in Buffalo, New York. He was one of the outstanding halakhists of the movement, was president of the Rabbinical Assembly from 1958-1960, a leading member of the Committee on Jewish Law and Standards from 1948 until his death in 1979.
As a leading authority on halakha he authored many important teshuvot (responsa), many of which were published in his influential "Responsa and Halakhic Studies". From the 1950s to 1970s, he wrote a comprehensive guide to Jewish law which was used to teach halakha at the Jewish Theological Seminary of America. In 1979 he assembled this into "A Guide to Jewish Religious Practice", which is used by laypeople within Conservative Judaism.