GUIDE to Hirschman, The Concept of Interest: From Euphemism to Tautology

What was the original meaning of 'interest' in the 17th and 18th century? What was 'interest driven' action like?

What were the benefits of an interest-based social order?

How was later interest diluted?

Hirschman concludes, that "More civilized political circumstances necessarily imply a less transparent and less predictable society." What is his argument leading to this conclusion?