Greg Mankiw has published an essay “Reflections of a Textbook Author”.

Prof. Mankiw estimates ~4mm copies of his books are in print.

Of interest to investors, he asks “Are textbooks too expensive?”

He is skeptical:
High fixed costs
Financial struggles of major... (2/n)
...publishers, citing bankruptcy of Cengage and stock price of Pearson.

Lack of competitive entry into the industry.

On the principal-agent problem of Professor & student: doesn’t explain the *change* of prices.