The Sagan Diary, by John Scalzi
Short story in John Scalzi's Old Man's War series, goes between The Ghost Brigades and The Last Colony...
Wow, just wow.
This was achingly beautiful.
It's a diary of Jane Sagan as she's ending her Special Forces career and getting ready to become a "normal" human with Zoe and John. Everything she wants and fears, how she feels about her identity and if she's going to lose whatever it is that makes her her after that change.
It's so incredibly intimate and adds so much to her as a person, and we already know a lot about her after Ghost Brigades!
So yeah, I loved this.