The name of this list is tongue-in-check, coming from the idea that bisexuality is often invisible. This ninja of sexualities hides in plain sight until the character we think we know well suddenly expresses an interest in someone of the opposite gender from their previous partner, or their orientation is simply declared outright.

This list should highlight books that surprise the reader with a primary character’s bisexuality. Their orientation must play some role in the plot or ongoing character development. Books that are primarily coming-out stories where the character is questioning their own sexuality should be avoided. Remember: The ninja knows exactly where they are at all times, it’s everyone else that’s surprised.

I want to highlight these books because they challenge reader’s assumptions and stereotypes around sexual orientation and promote bisexuality as a stable, long term identity.