# What are Book A, B and C?

BTI's three answers to how many bytes back a token, from widest to narrowest.

URL: https://blockspace.wiki/answers/what-are-book-a-b-and-c/

They are BTI's three answers to how many bytes back a token. [Book C](https://blockspace.wiki/glossary/book-c/), the content book, counts the artifact bytes alone. [Book B](https://blockspace.wiki/glossary/book-b/), the regional book, adds the structure the token's operations wrote, read or moved through. [Book A](https://blockspace.wiki/glossary/book-a/), the inclusive book, counts whole transactions bought for the token, shared where shared. On every entry, C ≤ B ≤ A.

Sources:

- Blockspace Holdings records
- block.space docs: BTI · https://block.space/docs/bti

Updated: 2026-10-20