The Lotus Caves by Samuel Youd (under the pseudonym of John Christopher), is a science-fiction novel first published in 1969. The story revolved around two teenage boys who live in a colony on the Moon. The year is 2068 and the colony live inside The Bubble, a large dome that composes their entire world. The two teenage boys, Marty and Steve, grow bored and they decide to explore, but find something completely unexpected.The Lotus Caves is widely accepted as one of the best sci-fi books that appeals to both children and adults. The review website Crossoverguide says, "Just because this is an older book it often gets overlooked. Don't make any mistakes, The Lotus Caves is a modern classic."