Can someone give me a detailed analysis of the character Colonel Calloway in the novel The Third Man by Graham Greene?

Colonel Calloway is the narrator of The Third Man. He is a former Scotland Yard detective who was made a colonel in the British army. Right away, the reader knows he is a rational man, as he says the following:

Rollo Martins believed in friendship, and that was why what happened later was a worse shock to him than it would have been to you or me (you because you would have put it down to an illusion and me because at once a rational explanation—however wrongly—would have come to my mind) (9-10).

Immediately after meeting Martins, a novelist, Calloway understands Martin's motivations. Unlike the romantic Martins, Calloway is a realist, a person who likes to look at the facts in an unbiased way.
Calloway is perceptive and a close observer, and he is able to wheedle information out of Martins. He asks questions about Lime's childhood and probes him by saying, "That sounds like a cheap novelette," (22) after Martins praises Lime. Calloway says, "I was anxious to vex him—one learns a lot that way" (22). In other words, Calloway, a careful observer of others, knows how to pump Martins for information, and he can make Martins annoyed so that Martins shares what he knows. Calloway is a seasoned detective and a person who knows how to get the truth out of others.
Later, in return for Martins telling him some information, Calloway tells him that Harry Lime was a racketeer who was involved in selling watered-down penicillin that caused the deaths of children. This information is a shock to Martins. While Martins is an idealistic character who becomes unwittingly involved in the intrigue of broken-down postwar Vienna, Calloway is a more hard-boiled, realistic character who sees clearly who Lime was and who destroys Martins's idealism.