Suggest me books related to espionage

I recently picked up this book called 'the game' by Tom wood and it was my first book involving any kind of action and what fascinated me about this book was how the main charcter who is a assasin and works for the CIA and how he evaluates everything around him. The author writes about his inner thoughts and what goes into to all his actions and it's something I have come across for the first time because in medium like films it mainly relies on action and not on what the characters are thinking. Please suggest me similar books which involves action and espionage but also gives the reader a peek into the mindset of the characters performing such actions related to espionage. Thanks!