Richard Dawkins spends five lectures making the case that human beings are evolved animals, not exceptions to nature, and that biology explains itself without appeal to design. Recorded for the Royal Institution Christmas Lectures in 1991, a tradition Michael Faraday started in 1825, the series opens with Dawkins comparing the human body's engineering to man-made machines, using a totem pole to talk about ancestral history. Later lectures turn to rocks and crystals to strip away the appearance of design in nature, and to stick insects and leaf insects whose camouflage shows evolution solving the same problem from different starting points. One lecture builds around a girl who told Dawkins she believed flowers exist for people to enjoy, a comment he uses to unpick the assumption that nature exists for humanity's benefit. Douglas Adams appears as a guest across the run, and the lectures rely on live demonstrations and specimens rather than narration alone to make their points.