This was a quick summer-type read. Not my usual genre, but I am a sucker for reading letters, even if they're fictional. Four girls are required to write pen-pal letters in school and from there a deep, lasting friendship develops between them. The author handled the sense of growth between these four from their teens to their forties pretty well. It is obvious, through the letters, how their friendship supports one another through some difficult times, even though they are not living near each other.