Paul R. Pillar as a Source

On the back of the TUFP book it gives a brief bio about the author Paul R. Pillar. It states that he was the assistant to Director of Central Itelligence to William Webster. I find this very interesting because Webster was at one point the director of the FBI and then later on made the director of the CIA. In a book I am reading called Why America Slept: The Failure to Prevent 9/11 the author says that when Webster became the head of the CIA he brought a lot of his colleagues from the FBI to take authoritative positions. One comment about the former FBI director taking over was that that the "CIA would rather be run by a Cub Scout den mother than the former head of the FBI." My question is this, did Paul Pillar start out in the FBI and transfer over to the CIA with Webster, what were Pillar's thought about having Webster in charge of the CIA?