Who is Fowler and what is his first authentic thrill of the day?

Fowler is a young writer who wants to write a book on detectives. He comes to meet Ausable, a secret agent, to know about the experience of being a spy and the kind of life a spy has. However, he gets disappointed because Ausable does not have the appearance as that of an agent. His first authentic thrill of the day was when he saw a man standing before them in Ausable’s room holding a small automatic pistol in his hand.