I’m Waiting for You: And Other Stories by Kim Bo-young

In the titular story, a man writes letters to his fiancé from a spaceship while he travels back in time. Their plan was to be married on Earth, before it was destroyed. The second novella-length story has awesome world building and a fear-mongering alien prophet. These are inventive speculative ideas told in straightforward prose. Fans of Ted Chiang and Ken Liu will love this book.  —Jason