While Italy and France possess an ample literature relating to Galileo, his oft-discussed fate and memorable achievements, very little has been written in Germany on this hero of science; and it would almost seem as if Copernicus and Kepler had cast the founder of mechanical physics into the shade. German literature does not possess one exhaustive work on Galileo. This is a great want, and to supply it would be a magnificent and thankworthy enterprise. It could only, however, be carried out by a comprehensive biography of the famous astronomer, which, together with a complete narrative of his life, should comprise a detailed description and estimate of his writings, inventions, and discoveries. We do not feel ourselves either called upon or competent to undertake so difficult a task. Our desire has been merely to fill up a portion of the gap in German literature by this contribution to the Life of Galileo, with a hope that it may be an incentive to some man of learning, whose studies qualify him for the task, to give our nation a complete description of the life and works of this great pioneer of the ideas of Copernicus. We have also set ourselves another task; namely, to throw as much light as possible, by means of authentic documents, on the attitude Galileo assumed towards the Roman curia, and the history of the persecutions which resulted from it. To this end, however, it appeared absolutely necessary to give, at any rate in broad outline, a sketch of his aims and achievements as a whole. For his conflict with the ecclesiastical power was but the inevitable consequence of his subversive telescopic discoveries and scientific reforms. It was necessary to make the intimate connection between these causes and their historical results perfectly intelligible. In the narration of historical events we have relied, as far as possible, upon authentic sources only. Among these are the following:— 1. Galileo’s correspondence, and the correspondence relating to him between third persons. (Albèri’s “Opere di Galileo Galilei.” Vols. ii., iii., vi., vii., viii., ix., x., xv., and Suppl., in all 1,564 letters.) 2. The constant reports of Niccolini, the Tuscan ambassador at Rome, to his Government at Florence, during and after Galileo’s trial. (Thirty-one despatches, from August 15th, 1632, to December 3rd, 1633.) 3. The Acts of the Trial, from the MS. originals in the Vatican. 4. The collection of documents published, in 1870, by Professor Silvestro Gherardi. Thirty-two extracts from the original protocols of the sittings and decrees of the Congregation of the Holy Office.[3] 5. Some important documents published by the Jesuit Father Riccioli, in his “Almagestum novum, Bononiæ, 1651.”[4]