The race has WR holder Brigid Kosgei, Olympic champion Peres Jepchirchir, defending champ Yalemzerf Yehualaw and Sifan Hassan making her debut. Plus a US showdown with Emily Sisson and Kiera D'Amato and Genzebe Dibaba, Almaz Ayana and Berlin Marathon champ Tigist Assefa. London organizers don't shy away from calling it the greatest women's field in history. LRC analysis coming soon.