2. Mythology (**Possible Spoiler***): Both Sirius Black and Remus Lupin's names are rooted in mythology. Sirius is a bright star situated in the constellation Canis Major, also known as the Big Dog. The Sirius Star is frequently referred to as the Dog Star. In Latin, 'Lupo' means wolf, and Remus is one of the twin brothers raised by a female wolf (lupa) in Roman mythology.
It was difficult to find very much trivia about this book in the series, so that's all I have come up with for now. But enjoy the cover art!