Cautionary Tales' host Tim Harford has a new book - The Data Detective - setting out ten commandments for understanding the numbers, charts, graphs and statistics that bombard us every day. In this free extract, Tim explains his extra "golden" rule that allows us to observe all his other commandments - be curious. Enjoy.

Cautionary Tales returns February 26.

The Data Detective (Riverhead Books) is published in the US and Canada on February 2. The same book is available elsewhere under the title How to Make the World Add Up.

(Audio excerpted courtesy of Penguin Random House Audio from The Data Detective by Tim Harford, narrated by the author.)