Rabbi Kolatch has authored numerous books, the most popular of which are Great Jewish Quotations, How to Live a Jewish Life, What Jews Say About God, This Is the Torah, and the best-selling Jewish Book of Why and its sequel, The Second Jewish Book of Why. Several of his works deal with nomenclature, about which he is an acknowledged authority. The New Name Dictionary and The Complete Dictionary of English and Hebrew First Names are his most recent works on the subject. Other books by the author include Our Religion: The Torah, The Jewish Heritage Quiz Book, The Jewish Mourner's Book of Why, Who's Who in the Talmud, and The Family Seder.

In addition to his scholarly work, Rabbi Kolatch is interested in the work of the military chaplaincy and has served as president of the Association of Jewish Chaplains of the Armed Forces and as vice-president of the interdenominational Military Chaplains Association of the United States.