The White Mountains (The Tripods #1)

Sam Youd, who wrote under a number of pseudonyms is particularly noted for his works written as John Christopher such as the Tripods Trilogy or the Sword of the Spirits Trilogy. Sam Youd was born in Huyton, Lancashire (though Youd is an old Cheshire surname). He adopted the name Christopher Samuel Youd for his professional writings, leading to the widespread but mistaken belief that that was his birth name. Throughout his life he was known simply as Sam to his friends and acquaintances.