I'm writing a book that begins in 1918. Yesterday, after I typed out "WWI" for the tenth time, it started to look very … wrong. Was it the "I" looking too spindly next to the big fat "W"? Or did it just seem wrong to call a monumental, global convulsion, in which sixteen million people died, by a nickname that looked a little too much like the World Wrestling Federation logo? I skidded to a halt, staring at my computer screen, trying to figure out how to write "World War One" properly.

The...