The Tripod Trilogy is a series of novels by John Christopher first released in 1967 that focuses on the fictional personal account of Will and his attempts to escape being mind-controlled by alien oppressors. The series has had a TV series adaptation produced by BBC and Seven Network. The story takes place in Europe after the world has been reverted to a pre-industrial era due to alien invaders inhabiting giant machines called Tripods. Personally one of my favorite novels and probably my most memorable childhood memory, each book has an amazing story to offer, although I feel 'The Pool of Fire' has a rushed plot. There are three books in the main timeline and a fourth book detailing the first encounter humanity had with the tripods, shown below. This book follows the description of the conquest given in the second book of the main trilogy.
The original trilogy:
The White Mountains (1967)
The City of Gold and Lead (1967)
The Pool of Fire (1968)
Prequel:
When the Tripods Came (1988)