This is the concluding volume of Deirdre McCloskey's trilogy on the near-miraculous enrichment of the world in the last few hundred years. My takes on the first volume, The Bourgeois Virtues, is here; on the second, Bourgeois Dignity, here.
To recap somewhat: the enrichment is something that needs explaining. Humankind muddled around for millennia, stuck in a rut of poverty and oppression, the majority of lives cut short by violence, disease, or some other symptom of deprivation. But starting around the 16th century or so, a hockey-stick increase began in northwest Europe and Great Britain, giving rise to the once-unthinkable widespread prosperity we live in today. Why there, and not somewhere else? And why then, instead of before, after, or never?
McCloskey's plausible and compelling argument … well, it's right up there in the subtitle, isn't it? It was a revolution of ideas, primarily ones that gave respect and legal protection to what McCloskey terms "trade-tested betterment". (That's kind of a clunky phrase, but it's less likely to be misinterpreted than the venerable terms "capitalism" and "entrepreneurship".) McCloskey presents her evidence in streams both wide and deep: how the political and religious climate changed; how the bourgeoisie were depicted in literature, painting, opera, plays, and so on. Alternative explanations for the great enrichment are considered and debunked.
Opposed to the bourgeoisie, since around the mid-19th century, are what McCloskey dubs the "clerisy". Think Sinclair Lewis, and his contempt of George F. Babbitt, multiplied in time and space. (Or think Nancy Pelosi, who rhapsodized that Obamacare would allow people to shuck their stupid day jobs and become "a photographer or a writer or a musician, whatever".)
This could be as boring as mud, but McCloskey's prose is witty and playful, with plenty of fun references (Mae West quoted on page 113; a Monty Python reference on page 628; and many more).
My standard disclaimer: this is a scholarly work, on a matter of ongoing academic controversy. I think McCloskey makes a pretty good case for her side, but (admittedly) I'm only seeing the one side. That said, there are (to my mind) irrefutable insights on just about every page here; even if you don't buy the whole enchilada, you'll come out smarter than you went in.