This comprehensive account of the horrific events of September 11, 2001 has been called “ultimate”, the “definitive” and the “first panoramic, authoritative account of 9/11." The book was written by the husband and wife team Anthony Summers and Robbyn Swan (Summers is English and Swan is an American). While the couple has extensive biographical writing experience (Marilyn Monroe, J Edgar Hoover, Frank Sinatra and Richard Nixon) neither had previously written about or has training in, intelligence and/or counter-terrorism.
If you are looking for positive things to say about the book, one might be that at least it does not consider the more outlandish conspiracy theories that flourished in the wake of the attacks and continue to this day.
They do seem to be fair-minded in their criticism of the Bush administration where many others are much more harsh. Summers and Swan conclude, as do many others, that the chief failing of the administration was that they were not adequately prepared for an attack of this magnitude, a conclusion that many other critics have also reached.
Another positive is that the authors do take the time to examine some of the more troubling, if far-fetched, claims about the attacks. One of those claims was that the CIA met with Osama Bin Laden in order to "negotiate" with Al-Qaeda. Another is the contention that the CIA had attempted to hire the hijackers, then covered up their plan in order to keep the FBI from finding out, and then orchestrated the attacks to keep from being discovered. This is a tenuous "positive" however, because although they do examine the claims, their insinuation that there is something to the charges, with absolutely no evidence, can hardly be called a good thing.
Perhaps the most positive thing to say about the book is its attention to data from both primary and extensively from secondary sources. Summers and Swan cite official reports, quote journalists, and make use of many other books and transcripts concerning the attacks.
Finally, their prose style is often enjoyable and keeps the book from being overburdened by their extensive data. Still, as many have concluded, this book doesn't offer much new other than to commemorate a terrible anniversary.