This Perfect Day by Ira Levin

From the author of Rosemary's Baby and The Boys from Brazil comes this story is set in a seemingly perfect global society.
Uniformity is the defining feature; there is only one language and all ethnic groups have been eugenically merged into one race called "The Family."
For centuries, mankind longed for a world without suffering or war. The Family made that dream come true. They have triumphed. Programmed, every need satisfied, they knew nothing of struggle or pain. They had mastered... perfected Earth.
But for one man, perfection was not enough. For Chip, it was a nightmare. The Family was a suffocating force of evil. His dream was to escape... and destroy!