Yep, seven stories total in 'Memory's Legion'. They're all the official Expanse novellas. 'The Butcher of Anderson Station' (Fred Johnson's past), 'Gods of Risk' (Bobbie Draper's family on Mars), 'The Churn' (Amos's origin story), 'The Vital Abyss' (a protogen scientist's monologue), 'Strange Dogs' (Cara and Xan on Laconia), 'Auberon' (Governor Rittenaur's rule), and 'The Sins of Our Fathers' (the very end of the story). It's the perfect gift for someone who's read the main books but missed these deeper dives. The physical book has a great cover, too.
The philosophical through-line is impossible to miss. From the relentless, amoral drive of Epstein to the communal survival instinct in the Belt, these stories ask what it means to be human under extreme pressure. They connect by each being a different answer to the same question. When you read them together, you get a spectrum of humanity, from the monstrous to the heroic. It's a deeper connection than plot.
Meh, it's an epilogue. Does 'The Return of the King' appendix add new canon to Lord of the Rings? Kinda, but it's mostly for superfans. Same energy. If you loved the series and need to know every last detail, you'll want it. If you were satisfied with the ending of 'Leviathan Falls,' you can probably skip it and not miss any huge, universe-shattering revelations. It's a quiet, character-driven coda. It adds canon, but it's not critical path for the main plot.
Through the lens of work. What do these people do all day? The medic treats patients. The linguist analyzes language. The engineer runs tests. The governor administers. The collection is fascinated by the daily grind of keeping a interstellar civilization running (or watching it break down). Exploring a character often means exploring their profession, their expertise, and the small, specific problems they solve. It's a very blue-collar approach to space opera that The Expanse always championed, and here it's dialed up to eleven. The drama comes from doing your job under impossible pressure, not from wielding a spaceship like a hero.