What do you call a book which contains information on all branches of knowledge?

There isn't a single, universally accepted term for a book containing information on all branches of knowledge. However, here are some possibilities, depending on the specific focus and tone:

Formal:

* Encyclopedia: This is the most common and straightforward term. It refers to a comprehensive reference work that provides summaries of knowledge on a wide range of subjects.

* Compendium: This term implies a systematic and concise collection of information.

* Lexicon: This term emphasizes a collection of terms and definitions, though it can also be used more broadly for a comprehensive book.

* Treatise: This term implies a more in-depth and scholarly approach to knowledge.

* Panorama of Knowledge: This phrase emphasizes the broad scope of the book's coverage.

Informal:

* Book of Everything: This playful term emphasizes the book's ambition to cover all knowledge.

* Universal Knowledge Base: This term highlights the book's aim to be a comprehensive repository of information.

* The Ultimate Guide: This term implies that the book is the definitive source for all knowledge.

Ultimately, the best term to use will depend on the specific content and purpose of the book.