Intrigued by the prospect of discovering how the WSJ went about its process of investigative journalism, I started in hungrily on this. It didn't disappoint, especially for the 1st three-quarters of it. Even if you're not that interested in the details of Enron's fall, the way the reporters pieced their early scoops together really shows how much it was the result of using common sense to put many many pieces of a puzzle together. It kicked off with an uncharacteristic resignation by a CEO, then ranged from obscure financial descriptions, nurtured sources from years of earlier work, a lot of background understanding of how energy markets worked, knowing when to trust and how to read the reactions of a company PR man, dropping hints in stories of potential findings and relying on reader's confidential feedback to pick up new leads... etc, etc. What was very curious to me, too, was their detailed descriptions of key character's personalities, families, career history, motivations. I think this distinguishes the journalist/detective from the legal prosecutor, the latter is trying to make a criminal case, and thus requires hard evidence that can be pieced together, and cannot rely on guestimates formed through inference of a person's motivations. Yet sometimes those hunches are critical. In this sense it reminds me of Chesterton's short stories, where the crime is often solved by trying to understand the criminal's motivation, then fitting the facts around that cornerstone.
The last chapter goes slowly though, it's thick into unravelling the lessons from Enron, and reads like an extremely long op/ed. Still, on the whole, excellent.