One of Putin’s instructors criticized Putin for his “lowered sense of danger”—a serious flaw for a potential spy.
The Man Without a Face: The Unlikely Rise of Vladimir Putin, Masha Gessen (UK) (US)
Also from that book, which I read in 2017:
Putin claims not to have taken part in anti-dissident work but has shown in interviews that he was thoroughly familiar with the way it was organized, probably because he was lying about not having done it.