From Hitler's Doorstep Book

This was a VERY interesting read.
His recap of the true nature of Iraqi al-Qaeda links was insightful and a welcome splash of reality to all the neocon Iraqi-al-Qaeda link allegations I came across in Stephen Hayes' Cheney: The Untold Story of the Most Powerful and Controversial Vice President in American History, which incorrectly uses Tenet as a mouthpiece to promote and defend its neocon agenda.
He gives an excellent account of the CIA's pre-9/11 operations against al-Qaeda, and although Gary Berntsen in Jawbreaker: The Attack on Bin Laden and Al-Qaeda: A Personal Account by the CIA's Key Field Commander severely criticizes Tenet for being a lax, stupid DCI who was hellbent on downsizing the operations directorate, that is not true at all.
One of the reasons I checked this out was because I'm intensely interested in the 2001 portion of the war in Afghanistan, and Tenet's chapter "Into the Sanctuary" doesn't disappoint. The inner workings of the CIA are very interesting. He also does an excellent job of covering his ass.
The CIA has always been an interesting organization to study, and I believe that one of the reasons why it is criticized for intelligence "failures" so much is because few people really know how it works.
Also amusing were Tenet's many awkward cultural interactions with foreign officials.
Occasionally, though, Tenet jumps all over the place, but this doesn't hamper the story that much.
I don't think he does a good job describing the CIA' operations in Iraq, though.
Also, if you've read Cobra II: The Inside Story of the Invasion and Occupation of Iraq, then Tenet's account of the failings of postwar Iraq, "Mission Not Accomplished" isn't going to be news, you can just skip over that.
*Also, the first chapter, Tenet claims he had a conversation with Richard Perle on September 12, but Perle was in France at the time.
*He characterizes Tina Shelton as a naval reservist, but she was actually a DIA analyst with 20 years' experience.
(The Weekly Standard was a little annoyed by his correct analysis of Iraqi al-Qaeda linkages and fair portrait of Richard Clarke and Bill Clinton, so they pointed this out, apparently to lower Tenet's credibility)
Also, see Steve Coll's book Ghost Wars: The Secret History of the CIA, Afghanistan, and bin Laden from the Soviet Invasion to September 10, 2001 for a good and fair portrait of Tenet.