English summary: 800 sundials of the Antiquity are known and preserved in museums. There are tens of thousands of them in Europe built between the Middle Ages and today. France alone has more than 32,000. The vast majority of them are still in operation on churches, in gardens, on public buildings or on private houses. In A History of sundials in the West, Denis Savoie reminds us of the heritage of Greco-Roman gnomonics and then examines...