When writing an analysis of The Human Factor, there are several perspectives you could choose to take. The story offers rich exploration of multiple concepts such as age, racism and humanity, and your analysis could include one or all of them.

One approach to an analysis of The Human Factor would be a discussion of the racial tension, which the book touches on as part of Castle's motivation for leaking governmental secrets to the Communists. While Castle was in the Secret Service during World War II, his first wife was killed in the London blitz, and his guilt for failing to protect her is part of why he has such a strong sense of gratitude to Carson. Carson is the Soviet agent who helped him get his next wife, Sarah, out of prison after he broke apartheid laws with her. Apartheid was the system of racial segregation in South Africa, institutionalizing racial discrimination and ensuring the white population would be dominant over people of other races. To break apartheid laws was a serious crime.

Another perspective you could use in your analysis is the theme of youth and old age. Greene shows the fear of aging through the eyes of Maurice Castle, Doctor Percival, Colonel Daintry and Sir John Hargreaves. Each man has a different attitude about aging and a different strategy for coping. For example, Castle is distressed that he will not share old age with his younger wife, so he would rather get a different job as opposed to going into retirement.

Another approach would be a discussion of humanity. Maurice Castle is arguably the most human of the characters, basing his decision making on feeling he owes Carson, the Soviet agent who helped get Sarah out of prison. He makes these decisions even at great personal risk. Then we have Doctor Pervical on the opposite end of the spectrum, a cold, cynical man who does not even feel regret when his decisions lead directly to the death of an innocent man.