1634: The Galileo Affair is the fourth book and third novel published in the 1632 series. It is co-written by American authors Eric Flint and Andrew Dennis and was published in 2004. It follows the activities of an embassy party sent from the United States of Europe (Grantville) to Venice, Italy, where the three young Stone brothers become involved with the local Committees of Correspondence and the Inquisition's trial of Galileo Galilei.

The 1632 series, also known as the 1632-verse or Ring of Fire series, is an alternate history book series and sub-series created, primarily co-written, and coordinated by American author Eric Flint and published by Baen Books.