If Graham is "this century's (and perhaps history's) most important thinker on applied portfolio investment," what specific, persistent challenges or unresolved questions in portfolio management do you infer his theories uniquely and effectively addressed that had not been sufficiently solved before him?

Synthesized answer

The provided passages describe Benjamin Graham as "this century's (and perhaps history's) most important thinker on applied portfolio investment" [1]. His theories are credited with influencing and inspiring investors for nearly 70 years, and his book *Security Analysis* is still considered the "value investing bible" [1].

The passages highlight the enduring relevance and foundational nature of Graham's ideas, particularly through his "revolutionary theories" and "original thinking" [1]. However, they do not specify the particular, persistent challenges or unresolved questions in portfolio management that his theories uniquely and effectively addressed before him. The passages focus on the impact and lasting importance of his work, rather than detailing the specific prior problems his theories solved [1].

Synthesized from the book passages below. Chat with the book on Feynman for follow-up.