Why did Lehman fail?

Larry Ball has an important new monograph arguing, contra Bernanke, that during the recent financial crisis, the Fed could have saved Lehman Brothers but, unadvisedly, chose not to.  Here, James Stewart of the NY Times covers the Ball piece, and it includes this tidbit:

an internal Fed team assigned to value Lehman’s collateral reached a preliminary finding that the firm was narrowly solvent and the Fed could have justified a loan. But everyone was too busy to listen, and the report was never delivered to Mr. Geithner, Mr. Bernanke or Mr. Paulson. This is consistent with Professor Ball’s findings.