A Brief History of Infinity. Infinity is just one of those topics that grabs your interest, not because it necessarily has any impact on your everyday life (though thanks to calculus, it does), but because it's genuinely mind boggling and has fascinated people for millennia.
Now, philosophy professor Adrian Moore is bringing a touch of the infinite to your ears with a 10 episode series of surprisingly bite-sized 15 minute programmes, starting today at 1.45pm on BBC Radio 4 (or listen later on iPlayer).
I know Adrian does a great job, as I appear in episode 5 on Friday, so I've seen him in action. It was also fascinating to discover that Adrian was inspired with an interest in philosophy by the same teacher who inspired me to write the book - it's really true what they say about a great teacher.
So buckle in to your radio/computer/phone or however you get hold of it for a fun ride...