Behind the demands of a baker for good bread and the brewer for good beer there are genetic variants that human beings have observed, preserved and developed. Through more than ten thousand years people around the globe have produced a vast biological diversity in our cultivated crop plants. Our Daily Bread tells this diverse history. Plant DNA reveals layers of history that supplement traditional archaeology. The world has three great grain cultures: the Asian based on rice, the American based on maize and the Eurasian based on wheat, rye, barley and oats. In Europe these have divided the continent into three bread zones: wheat in the West, rye in the East and barley or oats in the North. All originated in the Middle East. A few thousand years later they were grown to 70 degrees N in Norway and to 4000 meters in Ethiopia. Which mutations made this possible? What mutations enabled the phenomenal increases in grain production in the 20th century? Will this trend continue, so that the world can feed itself in 2050, when grains must not only feed us, but also supply raw materials and fuel to a bioeconomy?