Detailing events that take place between The Ghost Brigades and The Last Colony, Scalzi also wrote a novella called The Sagan Diary. He enlisted several friends to create an audio version, which is available on his blog:
I listened to it on Wednesday and thoroughly enjoyed it. The last chapter brought a tear to my eye. I preferred some actresses’ reading over the others, but I thought it was a unique way to present the work.
You probably won’t like it if you haven’t read the first two books, just FYI. But you were going to read them anyway, right? Do it.