Let me just say to begin with that it is flattering and daunting, in more or less equal parts, to talk about my new book on Vice President Cheney with four of its published critics: Jacob Heilbrunn in the NYT Book Review, Steve Clemons in the American Conservative, David Greenberg in Slate and Spencer Ackerman on his Attackerman blog. Paul Mirengoff of Power Line, who critiqued excerpts of the book that appeared in The Washington Post, has also agreed to join this conversation. That's a rare and commendable departure from the norm these days of talking mainly to people who already agree. As a reader, I'd love to see more crosstalk among thinkers across the political divide. I want to thank TPMCafe for setting that example.

It's hard to know where to start a conversation about Cheney. In ANGLER, I make the claim that you can't understand what happened these last eight years without knowing how often the vice president took the helm. But it's just as vital to know about the times when President Bush grabbed the wheel and veered off Cheney's course. Bush really was the Decider -- when he knew what was happening -- and he lost some confidence in his Number Two when Cheney nearly drove him off a cliff in the closing months of the first term. That story, which takes up the two climactic chapters of ANGLER, is one among many we did not know until now. Hundreds of people, many of them speaking on the record about previously undisclosed events, gave interviews for the book (and its predecessor, a series I wrote with partner Jo Becker). This Book Club conversation will go wherever you all please. In the next few paragraphs I'll throw out some of the stories, questions and criticisms that have come up most often in broadcasts and public events these last two months:

* What drove Cheney? His thoughts, more than just about anyone's, are a black box. Even so, I gathered a good deal of evidence for the proposition that the vice president has been fundamentally honest about his objectives, if not always about the underlying facts or the methods he employed. A lot of Cheney critics don't like to hear that, begrudging him a principled motive for policies they dislike. But ANGLER takes him seriously, and the public should too. Think about it this way: Cheney is a man of zeal, and zealots have had a lot more impact on history than self-serving hypocrites.

* Principle can be a flexible thing. Cheney sacrificed one principle, often enough, in service of another. I imagine he has as much regard as the next man for the virtue of truth, but if Dick Armey is to be believed Cheney flat-out lied to him about the intelligence on Iraq -- in pursuit of a larger goal of freeing Bush to fight what Cheney considered a necessary war. Cheney spoke often over the years about a president's need for honest brokers and a full range of policy advice, but just as often in the Bush White House he cut out those who might disagree. Some of the biggest decisions of the Bush presidency were made without the knowledge or advice of the national security adviser, secretary of state, secretary of treasury, administrator of the Environmental Protection Agency, or another top official with a stake.

* How did he become so powerful? No single answer here. The book is above all a study of power, its acquisition and exercise. Dan Quayle told me the fascinating story of his encounter with Cheney on Inauguration Day, in which Cheney explained the "different understanding" he had reached with the president. Quayle said the role was akin to Deputy President or "super chief of staff." In most cases, George W. Bush gave Cheney that authority. The vice president acted sometimes at Bush's direction (e.g. in settling federal budget appeals, which glazed the president's eyes) and sometimes with his tacit consent (e.g. in creating and overseeing aggressive new programs of intererogation and warrantless surveillance). He was a detail man serving a detail-averse commander in chief, and unlike those who served Ronald Reagan, another big picture president, Cheney had no weighty rival under Bush. He has a rare talent for identifying and pulling the hidden levers of government. And there's another factor at work: Cheney knows exactly what he wants. It's a very simple thing, really, but surprisingly rare when smart people face hard questions in the Situation Room. Or even when a group of friends tries to figure out what to eat, pizza or Chinese? By the time his rivals got off the fence, Cheney had often left the room and placed the order.

* What was Cheney's relationship with Bush? At first I thought their interaction would be out of reach of my reporting, since Cheney preferred to give his advice one-on-one. It turned out, though, that there were often two or three others in the room, and Bush sometimes briefed his closest aides about conversations they had missed. The relationship was complex and evolving, as most relationships are. ANGLER describes a trajectory in which Bush gave Cheney maximum deference in their early years together, but pulled back the leash as he grew more confident of his judgment and came to believe that Cheney posed a threat to his political health. Cheney could afford to be an anti-politician; Bush could not.

* Did Bush really know what Cheney was doing? The answer in my book is a qualified "yes" -- with several important exceptions, and hedged in general by the president's disinclination to focus on the fine points. One big exception was the warrantless NSA surveillance program: When the Justice Department came to believe that portions of the program were illegal, Cheney withheld that information from Bush for three full months as he tried to quash the insurgency.

* Has Cheney changed? Brent Scowcroft famously told the New Yorker that "Dick Cheney, I don't know any more." I explore this question at some length, including the hypothesis that Cheney's health -- nine cardiac events in eight years -- has altered his personality. I have to leave this in the unproved basket, and I show a lot more continuity than change in Cheney's views and behavior over the years.

* Why did people like Andy Card, Josh Bolten, Condi Rice, Steve Hadley, John Ashcroft, Jim Comey, Dan Bartlett, Karl Rove and a whole host of less famous names agree to talk to me on the record about Cheney? Different answers for different people, and I can pursue that if my interlocutors want to know.

* How can any reader know what to trust in a behind-the-scenes book like this, and how do I know what I purport to know? Though there's an honorable and absolutely vital place for anonymous sourcing, and ANGLER has its share, I made this book as transparent as I possibly could. There are 70 pages of Endnotes in fine print with citations to documents (public and exclusively obtained) and the subjects and dates of interviews. I drew upon contemporaneous notes as often as possible. So for instance, when I describe a meeting between Jim Comey and the president, I base the description in part on a BlackBerry message that Comey sent as soon as he left the Oval Office.

* Did Cheney overreach? For example: Did he succeed in his efforts to establish executive supremacy in making war and defining the law, or did the backlash from the public, Congress and the courts leave the presidency weaker than before? To me the result is mixed and, in part, yet to be determined. Some claims dear to Cheney have been repudiated by the coordinate branches of government, but in the fine print, and in practice, the vice president has often salvaged victory -- for now, at least.

All right, Book Clubbers. Have at me.