Galileo occupies an inflection point in the history of science and society. Born in 1564, Galileo changed the trajectory of science though his work in astronomy, physics and related fields. He invented various clever devices, and he used the telescope to push the boundaries of knowledge about our solar system and Earth's place in it. Galileo's discoveries, and the manner in which he presented them in his 1632 book Dialogue Concerning the Two Chief World Systems, hurled his fate into the judgements of the Roman Inquisition. Galileo recanted after he was found "vehemently suspect of heresy". The inquisitors sentenced Galileo with the unusual punishment of house arrest, where he remained until his death in 1642.

The Dialogue represented much more than a book on Copernican heliocentrism – that is, that the Earth rotates daily and revolves around the sun. The Dialogue also became a cudgel in the European conflicts between Catholics and Protestants, and the fate of the book in the midst of the Inquisition placed Galileo's lot in a precarious position. Did Galileo give a copy of the book to its Latin translator, which facilitated its distribution throughout Europe? Was Galileo's recanting of heliocentrism genuine, or did he continue to spread heretical views while under house arrest? How did Galileo run afoul of a Pope who had previously supported his work? The questions surrounding the Dialogue live on, and with us to decipher the controversy is John Heilbron.

John received AB and MA degrees in physics from the University of California, Berkeley in 1955 and 1958, respectively. He completed his Ph.D. in history, also at Berkeley, in 1964. He then taught at the University of Pennsylvania before returning to Berkeley in 1967, where he worked his way through the ranks of academia to a full professorship and director of the Office for History of Science and Technology in 1973. He served as Berkeley's Vice Chancellor in the early 1990s, and since then has been active as a professor emeritus.

Since 1996, John has also conducted research at the University of Oxford, and since 2012 at the California Institute of Technology. John is a member of the International Academy of the History of Science, for which he served as president from 2001-2005. He is also a member of The Royal Swedish Academy of Sciences, The American Academy of Arts and Sciences, and The American Philosophical Society. He is the recipient of many awards for his scholarship on the history of science. John has written numerous books, and today we discuss his latest, a beautifully written book entitled, The Ghost of Galileo in a Forgotten Painting from the English Civil War, published in 2021 by Oxford University Press.