I read The World Inside in 1971 when I was 14 years old, the very heart of the most impressionable years in an adolescent's life. The music you love at 14 is music that can stay with you all your life, your crushes and romances at 14 imprint you for your whole life, and if you are a reader, the books you read then can stay with you all your life.
I was a voracious reader then as now, and the early seventies were when I discovered science fiction writing. I had started with Asimov short stories as a lot of teens do, and progressed to SF short story anthologies. Some of my favorite short stories then and now are speculative fiction speculating about a future where everything has gone wrong. But this time, instead of a short story, it sustained itself for the length of an entire novel. The World Inside was one of the first full novels I read in the SF category, and it was definitely the first full length dystopia, weaving together several touchstone issues of the 60s: concerns about "the population explosion", what would happen if the "free love" counterculture continued to thrive, what would happen if mind altering drugs were legal and available to everyone, and whether city sprawl would overwhelm and eliminate all the rural space between the cities.
The novel is set in the year 2381. 75 billion people are living on Earth in enormous self-contained skyscrapers 1000 stories tall called urban monads, or urbmons. Each urbmon holds about 800,000 people, with 25 cities of 40 floors each. People on higher floors have higher social status, more money, and more power. Fifty of these superskyscrapers get grouped together in large metropolitan areas covering hundreds of miles like BosWash (stretching from Boston to Washington), Chipitts (stretching from Chicago to Pittsburgh), Berpar (from Berlin to Paris), and Shankong (from Shanghai to Hong Kong).
Instead of people being concerned about population growth, fertility is sacred and women are expected to have as many babies as possible. Contraception is obscene, jealousy has been abolished, there are no locked doors, and everyone has sexual access to everyone else. Usually the men go "nightwalking" from woman to woman, but women are also allowed to seek out anyone they desire, or seek sexual partners during the day. Everyone is required to have sex with anyone who asks. I quickly became desensitized to the frequent sex scenes, even though I had not read sex scenes before, because in context they were not very exciting. When sex is everywhere, sexiness is nowhere.
If you question the way things are, display inappropriate emotions like jealousy, challenge government decisions about how they move populations around, or otherwise do not fit in, they might label you as "flippo" and you could get sent down "the chute" where all the organic waste material is reprocessed and recycled into foodstuffs and energy.
I had been immersed in the "everything will be beautiful and we will all get along" world of Star Trek reruns, but I was also fascinated by people imagining alternate worlds where the Nazis won WWII, or for some other reason life on earth had gone terribly, horribly wrong. The World Inside was my first exposure to a full length novel that, from my point of view, depicted something even worse than terrible: a world where things were terrible AND almost no one openly acknowledged things were terrible AND people who were unusually bright or creative or otherwise perceptive (as I imagined myself to be) were the only ones who noticed that things were terrible. And they were punished for it. Sometimes killed for it. They were punished and/or killed for wanting more from life than the prescribed and strictly enforced social norms of people around them.
This blew my mind.
But paradoxically it also romanticized the idea of not fitting in, and made me even more proud to be an outlier and an outcast. Those were the years when I was beginning to strengthen my "question authority" muscles. I saw myself in the characters in The World Inside who went flippo and paid for not fitting in at the cost of losing their identities or losing their lives.
So as I read this book I knew I could never be someone who just accepted a life that was prescribed for me by powers that be, especially when their goal is to control as many people as possible without concern for individual emotions and needs. I hoped that in such a world I would have the personal courage to follow my individual dreams, feel my genuine emotions, and live authentically, even if it meant being branded as flippo. Even if the consequences of being branded as flippo included death, I would not be silenced!
Some people live their whole lives and ever get anywhere near making a decision to stand alone when necessary in the name of personal identity.
Reading The World Inside helped me make that decision at the age of 14.