This work, the 11th Volume of Trophoblast Research series, comprises collected papers presented to the 13th Rochester Trophoblast Conference (Summer 1996), held for the first time at Banff, Alberta, Canada. This edited volume hopes to recreate the main scientific themes discussed at this meeting for the reader. Established in 1961, the Rochester Trophoblast Conference is the oldest international conference on the placenta, and it became a formal corporate member of the International Federation of Placental Associations at the Banff conference.