"Economic Growth by David Weil.
One of the best textbooks I have ever read on any subject - this is the book to get. ... there is a huge amount here for professional economists and graduate students. ... this is the book that graduate students should read to discover the real questions that are in need of answers. I learned the most from this book."
Sounds interesting. The economics of the book are interesting as well, since Alex probably read the first edition, and maybe skimmed the second.
Weil's first edition is $2.10 + $3.99 shipping for "like new". At a $6 price, it's practically a no-brainer decision.
Second edition is $168 list, $148 actual on Amazon.com. At that price, the sunk cost fallacy would force me to read the book.