Galileo Galilei. Dialogo...Doue ne I congressi di Quattro giornate si discorre sopra I due Massimi Sistemi del Mondo Tolemaico, e Copernicano... Florence: Giovanni Batista Landini, 1632. First edition. Quarto. [viii], 458,  pages, with Errata leaf (2F6) and final blank present. Page 92 with correction slip supplying side note pasted in the margin. Woodcut device on title page, with thirty-one woodcut diagrams and illustrations, woodcut decorations and woodcut initials. Contemporary mottled calf with double-ruled borders and floral blindstamped devices in the corners. Text edges sprinkled red. Spine head renewed. Boards somewhat worn, with corners rubbed. Front hinge a touch tender after the endpaper. Minor marginal spotting to some leaves. Engraved frontispiece supplied in facsimile. Letter "H" added by hand to diagram on M8v. A one-and-three-eights-inch horizontal marginal tear to S6. Leaves 2B3/2B4 (with 2B4 missigned as "2B2") nested incorrectly and so bound. Signature of John Halkett, seventh baronet of Pitfirrane on title page. Bookplate of Halkett family on front pastedown. A clean copy, with wide margins, of Galileo's foundational work of modern science and philosophy. Galileo's statement and defense of the Copernican system of heliocentrism, a work which resulted in the author's 1633 trial for heresy in Rome. "The Dialogo was designed both as an appeal to the great public and as an escape from silence. In the form of an open discussion between three friends -- intellectually speaking, a radical, a conservative, and an agnostic -- it is 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. Astronomy and the science of motion, rightly understood, says Galileo, are hand in glove. There is no need to fear that the earth's rotation will cause it to fly to pieces. So Galileo picked up one thread that led straight to Newton. The Dialogo, far more than any other work, made the heliocentric system a commonplace. Every fear of Galileo's enemies was justified; only their attempts to stifle thought were vain" (Printing and the Mind of Man, second edition, p. 77). Bibliografia Galileiana 128. Carli & Favaro 28. Cinti 89. Dibner 8. Horblit 18c. Norman 858. Printing and the Mind of Man, second edition, 128. Riccardi I, 511. Sparrow 74.