"The Dialogo, far more than any other work, made the heliocentric system a commonplace." - PMM
First edition of Galileo's famous dialogue on two world systems, a major work in the history of science, in which he defends the Copernican system against the Aristotelian-based Church orthodoxy. Galileo here compares the Ptolemaic and Copernican world systems through a dialogue (in Italian) between a Copernican scientist named Salviati, a scholar named Sagredo, and a Aristotelian named Simplicio ("Simpleton") whose argument for geocentricity in rather simplistic terms seemed to parallel the beliefs of Pope Urban VIII and the Church. The publication of this book led directly to Galileo's trial for heresy and his subsequent house arrest due, and the Dialogue was placed on the index of forbidden books, where it remained until 1835.
In 1632, Galileo Galilei published his Dialogue Concerning the Two Chief World Systems, which supported the Copernican model that the Earth orbits the Sun, challenging the Church's geocentric view. His advocacy for this heliocentric theory, based on empirical evidence, led to severe repercussions. The Roman Catholic Church summoned Galileo to trial in 1633, resulting in his house arrest. This episode underscored the tension between emerging scientific inquiry and established religious beliefs, and it highlights the struggle for intellectual freedom and the gradual acceptance of scientific ideas that fundamentally reshaped our understanding of the universe.
As part of the Lincean Academy (Accademia dei Lincei), a group of scientifically-inclined naturalists named after the sharp-eyed Lynx, Galileo had been granted permission by the new Pope Urban VIII (the erstwhile Maffeo Vincenzo Barberini) to discuss this controversial subject in a book. However, the Pope was not happy with the result, and despite papal permission to publish such a work, Galileo was tried and confined for going against the Church dogma.
Eight years after Pope Paul V had forbidden him to teach Copernican theory, Galileo received permission from a new Pope, Urban VII, to discuss Copernican astronomy in a book, so long as that book provided equal and impartial discussions of the Church-approved Ptolemic 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 offence at what he felt to be its jibes against himself and ordered Galileo to be brought before the Inquisition in Rome. Galileo was condemned to permanent house arrest and forced to abjure all Copernican "heresy" - Norman Library catalogue.
...a masterly polemic for the new science. It displays all the great discoveries in the heavens which the ancients had ignored; it inveighs against the sterility, willfulness, and ignorance of those who defend their systems; it revels in the simplicity of Copernican thought and, above all, it teaches that the movement of the earth makes sense in philosophy, that is, in physics - Printing and the Mind of Man.
Rarity
Galileo's Dialogue has been getting scarcer in the market and has steadily increased in value during the last few decades.