Gian Vincenzo Pinelli (1535 – 31 August 1601) was an Italian humanist, born in Naples and known as a savant and a mentor of Galileo. His literary correspondence put him at the center of a European network of virtuosi. He was also a noted botanist, bibliophile and collector of scientific instruments.

He died in Padua, where he is commemorated by Vincenzo Pinelli, and by the Aroid genus Pinellia.

His enormous library was probably the greatest in 16th-century Italy, consisting of around 8,500 printed works at the moment of his death, plus hundreds of manuscripts. When he died, in 1601, Nicolas Fabri de Peiresc was in his house and spent some of the following months studying his library and taking notes from its catalogues. Pinelli's secretary, Paolo Gualdo, wrote and published (1607) a biography of Pinelli which is also the portrait of the perfect scholar and book-collector.

His collection of manuscripts, when it was purchased from his estate in 1608 for the Biblioteca Ambrosiana, filled 70 cases. Pinelli stood out among the early bibliophile collectors who established scientific bases for the methodically assembled private library, aided by the comparatively new figure—in the European world— of the bookseller.

His love of books and manuscripts, and his interest in optics, labored under a disability: a childhood mishap had destroyed the vision of one eye, forcing him to protect his weak vision with green-tinted lenses. Cautious and withdrawn by nature, detesting travel whether by road or canal boat, wracked by the gallstones that eventually killed him, he found solace in the library he amassed over a period of fifty years (Nuovo 2003).

Leonardo's treatise on painting, Trattato della Pittura, was transcribed in the Codex Pinellianus ca. 1585, perhaps expressly for Pinelli who made annotations in it. Pinelli's codex was the source for the Barberini codex from which it was eventually printed, ostensibly edited by Raphael du Fresne, in 1651 [1] Archived 2012-07-17 at the Wayback Machine. Pinelli's interest in the new science of optics was formative for Galileo Galilei, for whom Pinelli opened his library in the 1590s, where Galileo read the unpublished manuscripts, consisting of lecture notes and drafts of essays on optics, of Ettore Ausonio, a Venetian mathematician and physician, and of Giuseppe Moleto, professor of mathematics at Padua (Dupre).

Beside his Greek and Latin libraries of manuscripts his collection included the original Arabic manuscript from which was translated and printed the Descrizione dell'Africa of Leo Africanus.

He was among Europe's early botanists, and also collected mathematical instruments. He had taken musical instruction from the great madrigalist Philippe de Monte, with whom he continued a correspondence. He kept his amanuensis Camillus Venetus (Zanettus) busy.

In the field of botany, he collected herbs in his garden and corresponded with the father of Italian botany, Luca Ghini, who pioneered the techniques of drying and pressing plant material for a herbarium and whose papers he transcribed after Ghini's death, while the botanists who would be considered Ghini's heirs, like Andrea Mattioli and Ulisse Aldrovandi, clamored for them.

Pinelli's voluminous correspondence with the French humanist and book collector Claude Dupuy was published in 2001.

• Paolo Gualdo, Vita Ioannis Vincentii Pinelli, Patricii Genuensis. In qua studiosis bonarum artium, proponitur typus viri probi et eruditi. Autore Paulo Gualdo, Augustae Vindelicorum, Ad Insigne Pinus (=Markus Welser) (excudit Christophorus Mangus), cum privilegio Caes. Perpetuo, 1607
• Adolfo Rivolta, Catalogo dei codici Pinelliani dell'Ambrosiana, Milano 1933
• Raugei Anna Maria, (editor) 2001. Gian Vincenzo Pinelli et Claude Dupuy: Une correspondance entre deux humanistes (Florence:Olschki)
• Angela Nuovo, 2003. "Introduzione al catalogo di bibliografie" Archived 2007-09-28 at the Wayback Machine
• Angela Nuovo, A proposito del carteggio Pinelli-Dupuy, «Bibliotheca. Rivista di studi bibliografici» 2002/2, p. 96-115
• Angela Nuovo, Testimoni postumi. La biblioteca di Gian Vincenzo Pinelli tra le carte di Nicolas-Claude Fabri de Peiresc, in L'organizzazione del sapere. Studi in onore di Alfredo Serrai, a cura di Maria Teresa Biagetti, Milano, Ed. Bonnard, 2005, pp. 317–334
• Angela Nuovo, Gian Vincenzo Pinelli's collection of catalogues of private libraries in sixteenth-century Europe, «Gutenberg-Jahrbuch» 2007, p. 129-144
• Angela Nuovo, The Creation and Dispersal of the Library of Gian Vincenzo Pinelli, in Books on the Move: tracking copies through collections and the book trade, ed. by Giles Mandelbrote (et al.). New Castle, Delaware and London, UK Oak Knoll Press and The British Library, 2007, p. 39-68
• Grendler, M. 1980. "A Greek Collection in Padua: The Library of Gian Vincenzo Pinelli" Renaissance Quarterly 33: 386-416.
• —— 1981. "Book-collecting in Counter-Reformation Italy: the library of Gian Vincenzo Pinelli, 1535-1601", Journal of Library History, 16: 143-151
• Sven Dupre, 2000. "Galileo, Optics and the Pinelli Circle" History of Science Society meeting, Vancouver (Abstract)

• Callegari, Marco (2015). "Pinelli, Gian Vincenzo". Dizionario Biografico degli Italiani, Volume 83: Piacentini–Pio V (in Italian). Rome: Istituto dell'Enciclopedia Italiana. ISBN 978-8-81200032-6.