There are some good discussions about transgender representation in books going on, most of them focusing on the works of visibly queer and transgender authors. That got me thinking: What about strong transgender characters in other books?
There are a lot of novels and stories that presents negative and bigoted views of trans people, and in particular trans women. These characters are often sexualized, pathologized, ridiculed and presented as "traps" – a threat to cisgender adults and children.
However, there are also good books that do the opposite, books where the transgender side characters are just people like everyone else. I am going to present two books that passed my trans humanization test, and one that does not quite make it.
Summon The Angels by J.J. Campanella
Campanella has published two books in their Eddy Bratenahl series. These are exciting and entertaining crime/thrillers with some drops of horror added – well written and well researched.
Bratenahl is a policed psychologist at the Chicago Police Department. As such he is not really supposed to take part in investigations, but for reasons that will become clear to the readers of the books he does end up doing detective work anyway, due to his experience and contacts. 
Amanda Richards is introduced in book 1, A Sum of Destructions, but it is in the second book, Summon the Angels, she plays an essential role. You do not have to have read book 1 to read book 2.
Minor spoilers from here on.
When Amanda disappears she leaves her nephew Joshua in Bratenahl's care. He is soon engaged in the search for Amanda. The book then follows this search in parallel with a presentation of Amanda's past, including her training as a glass artisan in Japan.
Campanella has clearly done a lot of research on Japanese culture, and that alone makes the book worth reading.
The reason Campanella passes my trans humanizing test is because Amanda is presented as a complete human being. She is treated with respect by the author (and most of the other characters), and the story about her transgender journey and her life as a transgender woman seems true and believable.
By the way, there is another strong female character that caught my interest. Mary Kate Calderon is a veteran homicide detective working side by side with Bratenahl, and she has powers you rarely see in books like these. The book definitely passes the Behcdel test.
Summon of the Angels is a real page-turner, but what makes me love it is the way they go beyond pure entertainment and explores more existential questions like the role of evil and suffering in people's lives. Amanda's life story therefore becomes one of many threads in a tapestry depicting love and hate in a world that is often hard to understand and embrace.
