I worked in a similar field to Mr. Lynch's for another agency. The book was certainly entertaining to read and is one of the few fairly detailed books out there about FBI's and CIA's internal CI structure during that time. It was eerily similar to what I've experienced. However, the author does indeed come across as very negative. Although I could appreciate his "underdog" take on things (as CI practitioners are want to have), he basically complained about every job he had. It seems that he just simply didn't like to do anything in CIA outside of his very narrow specialty of writing CI reviews to protect the agency's HUMINT operations. That is a CI mission, but certainly not the only one.
More to that point, his condescending attitude toward his fellow CI Center (CIC) analysts in the Directorate of Intelligence (DI) component was disappointing. That element was one of the few U.S. Government organizations responsible for true all-source CI analysis on foreign intelligence services (which, according to the author, he wanted to do being chronically disrespected at FBI). CIC's production cycle was slower and more deliberate because their work could go as high as the President. That slower pace was an intentional feature, not a shortcoming. Their mission, like the rest of DI, had far more strategic impact than writing quick-turn CI "op-eds" for HUMINT cases. I couldn't help but feel like the author had a career-long identity crisis of having a DI personality while awkwardly trying to fit into the DO the whole time. Maybe he would have had a more fulfilling career if he stuck to CIC's analytical group instead of constantly setting himself up to be subordinated to case officers.