A writer of short stories, he was killed during World War I:

At the start of World War I, although 43 and officially over age, Munro joined the Royal Fusiliers regiment of the British Army as an ordinary soldier, refusing a commission. More than once he returned to the battlefield when officially still too sick or injured to fight. He was sheltering in a shell crater near Beaumont-Hamel, France in November 1916 when he was killed by a German sniper. His last words, according to several sources, were "Put that damned cigarette out!"

Seriously though, if you're not familiar with Munro (who wrote under the pen name of Saki), you should check out his work. In particular, take a look at the story Tobermory, which is about a talking cat that threatens to reveal all the secrets he's overheard at a dinner party.