Roo (many, many weeks ago) asked what I thought of Tim Harford's "The Undercover Economist".
Short answer: I loved it.
I first heard about it on a "Radio Economics" PodCast, where he read the introduction and the first chapter
The rest of the book was equally enjoyable.
The introduction sticks in my mind, however, because it was really a modern reworking of "I, Pencil". That is: not one person in the world knows how to start with raw materials and end up with pencil.
Milton Friedman explained it well: