This chapter introduces the three core principles of Darwinian agriculture. First, natural selection is fast enough, and has been improving plants and animals for long enough, that it has left few simple, tradeoff-free opportunities for further improvement. Therefore, implicit or explicit acceptance of tradeoffs has been and will be key to crop genetic improvement, through biotechnology or traditional plant breeding methods. Second, competitive testing of individual adaptations by natural selection is more rigorous than nature's testing of natural ecosystems merely by endurance. Although testing by endurance shows sustainability, there may still be considerable room for improvement. Third, we should hedge our bets against future uncertainty with a greater variety of crops and of research approaches. The chapter argues that this bet-hedging will require allocating some land and other resources to crops and research programs that seem less promising today but may outperform today's winners if conditions change.