Why do you think the author chose to focus on only three of Mitford children?

If there were six Mitford sisters and one brother, why was the focus on just 3 sisters? Surely, Nancy could have gone to one of them for advice about Diana's betrayal.

If the author widened her focus beyond the three sisters, she would have had a Game of Thrones-like narrative to contend with. Hodor!
By focusing on the three, the author is able to streamline plot and character interactions. The remaining sisters and Tom become somewhat composite. We have individuating mentions of them, but they do not confuse the narrative.

I think the three that were chosen were the closest to the situation. Although the others were affected, they were not directly involved in the dealings.

I agree with ABeman. More details on the other siblings would have weakened the narrative of the three main characters.

The three sisters were at the heart of what was happening in Europe. Remarkably, they could have affected the outcome of the war. Their story is fascinating

These 3 sisters led the most interesting lives - facism, 3rd Reich & spy catching. Plus, there stories were interwoven.

I believe the three sisters that the author selected were of the appropriate age for the plot. They were what would have been "coming of age", finishing school and interested in world affairs. Each one would have been making their decisions on what they felt was the correct political government for Great Britain. They were also now becoming aware of how politics would play a part in how their lives would be financially affected.

I think the contrasts between the three sisters perfectly represent the book's characters. There also was mention of the parents, and any more depth of family characters would have caused confusion and been overwhelming.

I agree with several above who commented that including more of the siblings would have weakened the plot. And let’s face it, they might not have been as interesting!

The three sisters were the most divergent in their points of view and were proactive in their beliefs, taking steps to act, while the remaining family members followed. However, I would have liked to know more directly from Jessica/Decca, representing the Communist role in England at the time; yet, I also realize that would have made the story more fragmented.

I think she chose the three sisters that were the most involved with Germany. Her story is based on Hitler and the war.

The three sisters represented the divergent views that were the most prevalent at the time.

I agree with Elizabeth K. They were the three most closely involved with politics and the driving forces of the time.