In 1543, as astronomer Nicolaus Copernicus lay on his deathbed, his colleagues brought him the final printed pages of De Revolutionibus (On the Revolutions of the Heavenly Spheres), the book he had worked on for many years. Though he would not live to hear of its extraordinary impact, his book ? which first posited that the sun, not earth, was the centre of the Universe ? is recognised as the greatest scientific work of the 16th century.

Four-and-a-half centuries later, astrophysicist Owen Gingerich embarked on an extraordinary quest: to see in person all extant copies of the book. He was inspired by two contradictory bits of information: Arthur Koestler?s claim, that nobody had read Copernicus?s book when it was published; and Gingerich?s discovery of a first edition of De Revolutionibus that had been richly annotated in the margins by the 16th-century astronomer Erasmus Reinhold, suggesting that Koestler was wrong.

After three decades of investigation, and after traveling thousands of miles, Ginegerich has written an utterly original book. Part biography, part exploration, his account offers new appreciation of the history of science.