Like Questions for a Soldier, this is just a filler that mainly repeats what we already know. (If you read the afterword, you'll see that he was compelled to write something for a special cause.)

However, Scalzi gets a little experimental this time and tries to look at his subject from different angles, both philosophically and linguistically. The result is interesting, but his (or Sagan's, as this is supposed to be verbatim from her brain) poetic phrasings are often a bit too much ("I have signed on for a mermaid’s sacrifice and will walk on knives for dumb love"), distracting from the quite touching notions this is meant to transport.