Luna by Julie Anne Peters is a young adult novel about a transgender teenage girl's transition experience. Despite being about the titular Luna O'Neill, born Liam, it is told from the first-person perspective of her younger sister Regan, who at the start of the story acts as Luna's Secret Keeper and the only person who understands her and sees the girl in her.
The situation is complicated by their conservative father, a "manly man" who tries to raise his "son" in these values as well, and Alyson, Luna's friend with Incompatible Orientation, who has a crush on Liam as a boy without knowing that such a person doesn't really exist. Meanwhile, on her front, Regan starts falling for a New Transfer Student called Chris, but a series of misunderstandings and Regan's schedule overlaps with helping Luna conspire to keep them apart...
Unlike a lot of Gender Bender fiction, the subject matter is very much not played for laughs.
This novel contains the following tropes:
- The Alleged Car: Two of them, Dad and Chris's. Luna's, however, is anything but.
- Attractive Bent-Gender: Zig-zagged. Regan actually thinks Luna looks more attractive than most GGs (genetic girls), but onlookers disagree when they realize who she is.
- Bittersweet Ending: Luna is disowned by Dad and has to abruptly drop school, but flies away to start her new life aided by Teri Lynn, looking forward to hormone therapy and SRS. Regan doesn't get her job back, but Luna passes on her belongings to her, and for the first time in her life she's free from the weight of her sister's secret disrupting her life. The novel ends with the sisters parting on good terms.
- Dysfunctional Family: It runs over generations, apparently, as we learn after meeting the grandparents.
- I Know You Know I Know: Both Regan and Mom know Luna's secret, but neither knows the other knows, and is afraid all hell will break lose if the other also finds out.
- Incompatible Orientation: Luna and Alyson. Both straight, though, obviously, Luna isn't straight in the same sense Alyson thinks. Luckily, they stay friends.
- Interrupted Suicide: Regan stops it. In fact, let's just say the story would have been a lot darker if Regan hadn't existed.
- Meaningful Name: Enforced in-universe. After discarding the initial choice for a female name, Lia Marie ("too close"), Luna chooses this name as "a girl who can only seen by moonlight" — very early on, when all she does is dress up in Regan's room. Regan also calls her "Moon Girl".
- Mentor: Teri Lynn to Luna.
- New Transfer Student: Chris.
- Never My Fault: Regan accidentally schedules a date with Chris while she's supposed to babysit, and instead puts Luna in charge of the kids while she's gone. She neglects to keep track of the time and gets back to find Luna rooting around in the lady of the house's closet and trying stuff on, and the father is barely stopped from assaulting her. Of course Regan is fired for this, and she proceeds to put the majority of the blame on Luna, even though she was the one who blew off her job and left kids she was supposed to be babysitting in the care of someone the parents had never met.
- Sadist Teacher: Bruchac appears like this to Regan at first, but she discovers that there's more than this to him.
- Secret Keeper: Regan.
- Secret Identity Identity: As expected given the subject matter, Luna is the real self while Liam is a mask she has to wear. Regan compares Liam letting Luna out to a butterfly emerging from a chrysalis... and then being forced to retreat back on the next day.
- Sensitive Guy and Manly Man: "Liam" and Chris, when Regan compares the two. Then again, the former isn't really a guy anyway.
- Supporting Protagonist: Regan, the narrator, is the "Watson" (in both senses, see below) to Luna, the title character, observing her struggles from the side.
- Trans Equals Gay: Discussed. Luna is repulsed at the mere mention of this misconception, which fuels her hatred for Hoyt.
- Trans Tribulations: Luna has an ultra-macho father who expects his sons to be masculine.
- Transgender: Luna, duh.
- The Watson: Regan's unfamiliarity with TS terminology makes Luna gradually explain it to her — and by proxy, to the audience.