The White Mountains (John Christopher)

Summary: Long ago, the Tripods--huge, three-legged machines--descended upon Earth and took control.  Now people unquestioningly accept the Tripods' power.  They have no control over their thoughts or their lives.  But for a brief time in each person's life--in childhood--he is not a slave.  For Will, his time of freedom is about to end--unless he can escape to the White Mountains, where the possibility of freedom still exists.  (from amazon.com)

Where can I find it?: Open eBooks app

Tags: Science fiction; Extraterrestrial beings; Dystopias; Fantasy fiction; Machinery; Twenty-first century; Liberty; Human-alien encounters