Their hands were huge, but finely moulded...their legs were stouter...their feet had lost their separate toes...blonde hirsute appearance...Their eyes were large, and often jade green, their features firm as carved granite, yet mobile and lucent.
Хотя роман содержит большое для своего времени количество новых фантастических идей (многие из которых оказали влияние на творчество других фантастов), основной целью автора была демонстрация эволюции человеческого разума и духа.