The development of the placenta was a pivotal event in evolution. The long and tortuous evolutionary road which led from egg-laying reptiles to present-day placental mammals like ourselves was an epic journey spanning over 300 million years. Without the placenta, we would still be laying eggs, instead of giving birth to live offspring. In Life's Vital Link, Y. W. Loke provides an engaging look at this remarkable organ, tracing the life of the placenta from the moment it is created within a fertilized egg, through its brief but eventful stay within the womb-usually around 270 days. Loke...