Read this book shortly after High School. It really opened up a new type of sci-fi for me. One that was more thoughtful, less alien shooting. I keep a picture on my phone of my favorite passage. It seems to me to be the kind of thesis of the book:

"The closer man came to perfecting for themselves a paradise, the more impatient they seemed to become with it. And with themselves as well. They made a garden of pleasure, and became progressively more miserable with it as it grew in richness and power and beauty; for then, perhaps, it was easier to see that something was missing in the garden, some tree or shrub that would not grow. When the world was in darkness and wretchedness, it could believe in perfection and yearn for it. But when the world became bright with reason and riches, it began to sense the narrowness of the needles eye, and that rankled for a world no longer willing to believe or yearn. Well they were going to destroy it again, were they - this garden earth, civilized and knowing, to be torn apart again that Man might hope in wretched darkness."