In 2008, the Library of Congress purchased a previously unstudied copy of Galileo's 1610 Sidereus Nuncius . Aware of rumours, later substantiated, of the emergence on the market of new Galileo forgeries and sophisticated copies, Daniel De Simone, then Curator of the Rosenwald Collection, exercised extreme cautious in checking this copy's authenticity. His introduction offers a fascinating and reassuring glimpse into the processes now involved in the acquisition of a rare book. Happily, examination of its watermarks and print against several other copies shows that the book block is authentic. Without having seen the original, I am curious about the atypical envelope-style pasteboard cover botched title Galil./Sidreus./1610, and presume that the impossible description of probably eighteenth-century endpapers (p. x) bearing a seventeenth-century inscription (xiii) is merely a slip rather than a giveaway. only explicit statement of the book's earliest provenance lies in the tricky inscription Ex libris dominici/Fratei-/Veronae which the volume glibly translates as the library of the Dominican friars of Verona (p. xiii). Dominican church of Santa Anastasia in Verona, if that is indeed the institution alluded to, did have a library, although this avenue of provenance research remains unexplored here and might prove fruitful. Whatever the copy's actual provenance, this is one of only four known copies never to have been trimmed (the others are at New Haven, Naples, and Venice), which is good news not only for deckle fetishists but also bibliographers: it provides an excellent example of the book in one of its two earliest states of production (the other is a fine paper edition, slightly smaller than this), before the trimmer's knife brought it down to size and into normal use.The copy is reproduced in colour facsimile, just slightly enlarged from the original. For some reason, the endsheets and back cover are not included, but all these are available, at three fabulous levels of magnification, online at http://www.loc.gov/item/2010667904/, where the colour palette is also deeper. facsimile is followed by a short guide supposed to help the reader through Albert Van Helden's translation, also supplied, although without his invaluable notes (a new edition of Sidereus Nuncius Or, Sidereal Messenger will be published by Chicago in November 2015). two lines not translated by Van Helden, the book's imprint, is here mistranslated: it doesn't take much Latin to work out that Superiorum Permissu, & Privilegio does not mean with permission and highest privilege. Similar standards render Della Porta's Magia Naturalis as The Magic of Nature turn Kepler's 1609 classic into Astronomic a Nova , transfer La Galla into a Jesuit and exclude Giordano Bruno from the Biographical Index while including several irrelevant figures. …