What is the passage on back of book called I know not a summary?

The passage on the back of a book is called a blurb.

It's a short, compelling description of the book, designed to entice readers to pick it up. It often includes:

* A brief summary of the plot

* Praise from other authors or critics

* Information about the author

* The genre of the book

* Keywords that describe the book's themes or topics

The blurb is crucial for marketing a book, and it can be the deciding factor for whether a reader chooses to purchase it.