January 31 - Zero

I didn't know that a lot of thought went into the invention of zero as a mathematical concept. It was actually the subject of much philosophical debate before it popped onto the scene.

Robert Kaplan has written a book about it called "The Nothing that is". It traces the history of zero "back to its origins as two wedges pressed into a wet lump of Sumerian clay" and explains how "it now forms part of the binary code which powers our computers".