The Universe, wrought for us by a supremely good and orderly Creator.

Mathematics is written for mathematicians.

In the first book I shall describe all the positions of the spheres, along with the motions which I attribute to the Earth, so that the book will contain as it were the general structure of the universe. In the remaining books I relate the motions of the remaining stars, and all the spheres, to the mobility of the Earth, so that it can be thence established how far the motions and appearances of the remaining stars and spheres can be saved, if they are referred to the motions of the Earth.

Astronomy is written for astronomers

For what could be more beautiful than the heavens which contain all beautiful things.

The strongest affection and utmost zeal should, I think, promote the studies concerned with the most beautiful objects, most deserving to be known.

The Universe, wrought for us by a supremely good and orderly Creator.