H. Beam Piper,
Graveyard of Dreams
“ Some of the other planets had been rich in metals, and mines had been opened, and atmosphere-domed factories and processing plants built. None of them could produce anything but hydroponic and tissue-culture foodstuffs, and natural foods from Poictesme had been less expensive, even on the planets of Gamma and Beta. So Poictesme had concentrated on agriculture and grown wealthy at it. ”
