What do you call book cover art that goes on the front and back?

There isn't a specific term for book cover art that goes on the front and back. However, you can describe it as:

* Wrap-around cover art: This emphasizes the continuity of the design across both the front and back covers.

* Two-sided cover art: This is a more general term that simply states the fact that the art is on both sides.

* Front and back cover art: This is a straightforward description that is clear and easy to understand.

* Continuous cover design: This emphasizes the artistic unity of the front and back cover art.

You could also be more specific depending on the actual design, like:

* Full-bleed cover art: If the art extends to the edges of both covers.

* Spanned cover art: If the art is divided across the front and back cover, but connected thematically or visually.

Ultimately, the best way to describe the cover art depends on the specific context and what you want to highlight.