“In about two months, December and January, [1609], he made more discoveries that changed the world than anyone has ever made before or since” (Swerdlow in P. Machamer (ed.), The Cambridge companion to Galileo (Cambridge, 1998).

First edition of Galileo's Mathematical Collections and Translations. Thomas Salusbury compiled and translated epochal writings by Galileo, Archimedes, Descartes, Kepler, Tartaglia, Torricelli into English for the first time, the first vernacular translation into any language, dramatically impacting the English-speaking world. 

This volume contains the first English translation of Galileo’s 1632 The Dialogue Concerning the Two Chief World Systems (Dialogo sopra i due massimi sistemi del mondo), Galileo’s controversial and highly celebrated defense of the Copernican system. "Eight years after Pope Paul V had forbidden him to teach Copernican theory, Galileo received permission from a new Pope, Urban VIII, to discuss Copernican astronomy in a book, so long as the book provided equal and impartial discussions of the Church-approved Ptolemaic system. Galileo's Dialogue concerning the two chief world systems held to the letter of this command: the device of the dialogue, between a spokesman for Copernicus, one for Ptolemy and Aristotle, and an educated layman, allowed Galileo to remain technically uncommitted. After the book's publication, however, Urban took offense at what he felt to be its jibes against himself and ordered Galileo to be brought before the Inquisition in Rome" (Norman 858). 

The Dialogo was suppressed by the Church five months after its publication and formally condemned in June 1633. Galileo's defense of "the Copernican heresy" resulted in his permanent house arrest. Soon thereafter he was forced publicly to recant his defense of Copernicus. The book remained on the Index Librorum Prohibitorum until 1823.

Also included is Galileo’s 1615 letter to the Grand Duchess Christina of Tuscany, published in 1636 as Nov-antiqua sanctissimorum patrum et probatorum theologorum doctrina, which asserted the independence of science from religious authority. Known today as the “Letter to Christina,” Galileo’s epistle delimits the authority of Holy Scripture in philosophical (scientific) controversies, and was only the second work of Galileo’s to be published in England. It preceded the Latin edition, published in London by Thomas Dicas, by two years and remained the only vernacular translation for two centuries. In this Galileo stated quite clearly that for him the Copernican theory is not just a mathematical calculating tool, but is a physical reality:

“I hold that the Sun is located at the centre of the revolutions of the heavenly orbs and does not change place, and that the Earth rotates on itself and moves around it. Moreover ... I confirm this view not only by refuting Ptolemy's and Aristotle's arguments, but also by producing many for the other side, especially some pertaining to physical effects whose causes perhaps cannot be determined in any other way, and other astronomical discoveries; these discoveries clearly confute the Ptolemaic system, and they agree admirably with this other position and confirm it.”

This letter circulated in manuscript and was brought to the attention of Cardinal Bellarmine, the principal theological advisor to the Pope. Bellarmine ruled that Galileo’s accommodation was acceptable if he could prove that the Bible had to be read some way other than literally, but first he required proof, and Galileo had yet no proof that the earth moved. Therefore scriptural passages suggesting a fixed Earth should be read literally. In 1616, however, the Inquisition declared heliocentrism to be "formally heretical." Subsequently, Copernicus’ masterpiece, On the Revolutions (1543), was, for the first time, placed on the Index of Prohibited Books. Galileo’s own trial was still 16 years away, but the stage had now been set, thanks, in part, to the Letter to Christina.

Folio, bound in full calf, with 4 engraved plates. Lacking the half-title, contents leaf, fly-title to The System of the World, and the errata leaf found at the end of the first part in some copies. Preliminary leaves show some restoration, occasionally encroaching on text. 2 parts in one volume. In very good condition with contents showing light browning in the upper margins. First editions are exceptionally rare. Book #BvC2451. $55,000.