Another clue is simply her occupation. A Kourier must be bold and brave to make deliveries to and for all classes of people in all types of environments. The attention to detail Stephenson gives to his characters is a good start in making a novel enjoyable. Even the lesser characters, such as the librarian, Squeaky and Fisheye, are fairly well developed before they expire fade out. The plot development is especially good, because it is interesting and exiting as well as being complex and thought provoking.
Chapters step from one main character to the next while still involving another character.
Though the narration is in third person, it seems very personal. This adds something to the plot that most stories can't produce. The active and passive parts of the story are in an effective ratio. The story line is not simple to follow, but it is so intriguing that the complexity and movement in the story adds to the to tone and mood of the story, rather than detracting from it, as is evident in poorly written stories. Another element that is especially remarkable in the story is the humor.