Nobel laureates are peer-reviewed experts. Most investment books are not so theoretical.

For all of these books, peer review is the best validation, better than popularity. Many best-selling book with lots of media coverage can be proven invalid by the market a few decades later.

In contrast, sometimes a theory is actually validated over a long horizon … like 200 years! This is basically Fama’s criticism of Shiller.

A peer-reviewed investment theory is more validated than a “popular” book, but not as validated as a chemistry theory. Asset pricing theories are hard to validate, esp. compared to phy/che/med theories. Very limited data available to use for validation.