1635: The Cannon Law is the sixth book and fifth novel published in the 1632 series by Eric Flint and Andrew Dennis. It is the second novel in the French-Italian plot thread, which began with 1634: The Galileo Affair and was published by Baen Books in 2006. The book explores the reactions of the Roman Catholic hardliners to Pope Urban VIII's actions in tolerating the new freedom of religion taking root in Central Europe during the climax of The Galileo Affair.

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.