Rabbi Leonard Cahan (1934-2018), originally from Philadelphia, Pennsylvania, was the rabbi and then rabbi emeritus of Congregation Har Shalom in Potomac, Maryland. Ordained at JTS, he held pulpits in Detroit, Michigan, and Oakland, California. He was a Navy Chaplain from 1961-1990 and served in Quantico, Virginia and Japan, and retired as the rank of Commander. Rabbi Cahan also served on the Jewish Welfare Board from sometime in the ‘70s until 2016. In the early 1990s, he undertook a complete overhaul of Rabbi Jules Harlow's Sim Shalom (Rabbinical Assembly 1985), separating it into Shabbat & Weekday volumes, which went to press in 1998. He also contributed substantially to reworking the 2014 JWB siddur into the edition published in 2017.