At first I disliked the letter format. But as I settled in, and met more characters, I enjoyed it. Having many actors read the different voices was a big help in understanding and keeping the characters straight. One issue I had was that Sybil’s dedication to letter writing made me feel guilty that I stopped writing to my friends and family years ago. The author makes a good case for why actual letter writing is helpful in sorting out our feelings, and a good mental and emotional exercise. I liked the everydayness of the letters, mixed in with some dramatic events.
The characters were believable, though necessarily somewhat flattened by space & time limits.