The Last Starship From Earth by John Boyd
In an alternate world, where Jesus was a rebel leader, the Pope is a computer and Hell is a planet orbiting a distant star, the state is controlled by the Church, the sociologists and the psychologists.
Mathematician Haldane IV falls in love with poet Helix, a forbidden pairing in this totalitarian state, where the population is strictly controlled by eugenics. They are discovered and sent for trial, leading them on the path to Hell and an unexpected chance to change society forever.
The first part of this book, with its illicit affair between different classes in a police state, is heavily influenced by Orwell’s 1984, but the final section veers off in a more overtly science fictional direction, leading to an unexpected yet satisfying conclusion.
SF author David Brin recently referred to this novel as a forgotten, lamented classic, and I have to agree. The writing style is a cut above the norm for late sixties SF, even if the treatment of the female characters is still decidedly ‘of its time’.
The blurb on the back of my edition, from none other than Robert A. Heinlein himself, states that this novel “belongs up at the top along with Brave New World and 1984.” Give it a go — you won’t regret it.