Leaders who live at transitional periods make their mark on future generations as well as on their own. An examination of Rav Hai Gaon's philosophical and halachic writings show his immeasurable influence. Author of the first work of practical halacha for merchants at the dawning of Jewish prominence in world trade, he was copied by many later writers, and his rationalist strain of Torah interpretation shaped the Rambam's thinking two centuries later. Though overshadowed by the giants that came after him, all of those giants were able to achieve what they did because of the path he paved for Torah scholarship.