Books on the intelligence community

Hi all, I was wondering if anyone had anyone non-fiction book recommendations concerning how intelligence agencies, like the CIA, operate. I know virtually nothing about the intelligence community that I haven't seen in film, literature or the media and I would love to know more. My seeking out this information ultimately stems from my wish to maybe one day write a fiction book about the intelligence community, in the likes of John le Carré. I would especially like to learn about Western espionage during the Cold War. I look forward to seeing your responses!