'Well, evolution goes in quantum leaps, but it doesn’t go that fast.’ 1980 was a time of profound change for Doctor Who, with a new producer and script editor both keen to overhaul the series at all levels. During the course of its 18th season the series would also undergo a complete change of its leading cast. Positioned in the middle of this pivotal season, Full Circle (1980) exemplifies the new production team’s vision, one that rejected the fantasy overtones of previous years and put a more science-driven ethos at the heart of the series. It attempts to present the concept of evolution to a tea-time family audience in an entertaining way, dramatising it by depicting the inhabitants of a spaceship and a primordial swamp in conflict with each other. But stranger elements lurk beneath the surface, forgotten and waiting to re-emerge. This book puts Full Circle under the microscope and discovers a mixed heritage of discredited science, pseudoscience and mysticism. It also considers the effect this story, the first to be written by someone who grew up as a fan of Doctor Who, had on the evolution of the series itself.