This French offensive was the second-largest battle on the western front in 1917. For years it shared with Passchendaele (Ypres 3) a reputation of being the height of futile self-immolation. Modern accounts offer a more balanced perspective. The talk covers the heavily polarised attitudes before the attack was launched, and then describes the battle and its outcome with some emphasis on aspects that were new, such as the first use of tanks by the French and the cave and quarry fighting. The rise of Petain to command the French army was a direct result of this watershed battle.