Now in 35th-anniversary editions, John Christopher's Tripod trilogy, about a race of three-legged machines who rule the planet, appears with a new introduction from the author and revised texts. The White Mountains introduces 13-year-old Will as he flees the capping ceremony, a rite of passage in which the Tripods enslave their subjects by fitting them with metal headgear, and heads to Switzerland's White Mountains in search of the world's only remaining community of free people. The follow-up, The City of Gold and Lead, finds Will and friends living in Switzerland and training to overthrow the Tripods. But he must travel to the City of the Tripods, from which few return, to acquire vital information. In the final installment, The Pool of Fire, Will and friends fight against time to defend the human race from extinction, the end result of the Tripods' scheme.