A bittersweet adventure tale told in the first person. Classic Heinlein, but not one of his best. Some have characterized this as Heinlein's foray into the fantasy genre, but it is science fiction. The inclusion of a hero with a sword and technology indistinguishable from magic does not equate to fantasy.
I read this partly because it appeared on the Goodreads list of fencing fiction that I maintain. The presence of fencing was interesting, but unrealistic considering the weapon the protagonist was using.
Heinlein's writing is good, with enough obscure allusions that Wikipedia and Google were helpful aids, which surprised me pleasantly. Unfortunately, the rampant sexism got in the way for me. (Heinlein, sexist? Nah. must be my imagination.) Although this story, like many of Heinlein's works, features a strong female character, she is a sex object first and foremost, as are all of the other female characters. As strong as she is, she is still portrayed as being slightly inferior. She becomes the protagonist's equal (or nearly so) only after the infusion of countless male personalities late in the story.