It has my vote for the single most brilliant SF book ever written.
Not SF, but an enjoyable read and it is FREE!
The rise and fall of diamonds
By Edward Jay Epstein
An enjoyable history of diamonds and De Beers.
Ian Fleming was in it up to his neck!
The author posts his one-time bestseller online for free.
A bit dated, but not much, if anything has changed.
http://www.edwardjayepstein.com/diamond/prologue.htm