The initial right to publish a work in its original language and format (e.g., a hardcover English book in the US).

Rights are rarely "all or nothing" and are typically split into specific categories:

The process varies depending on whether you are buying from a publisher or directly from a creator. 1. Identification & Research A guide to book publishing rights - Amita Parikh

Additional permissions for other formats or uses, such as: Digital/Audio: Rights for e-books and audiobooks.

Film, TV, or stage play rights, often acquired through an "option". How to Buy Publishing Rights