If you want to contribute to the Rizin book, you can do it at the Github repository. Suggested contributions include:
- Crackme writeups
- CTF writeups
- Documentation on how to use Rizin
- Documentation on developing for Rizin
- Conference presentations/workshops using Rizin
- Missing content from the Radare1 book updated to Rizin
Please get permission to port any content you do not own/did not create before you put it in the Rizin book.
See https://github.com/rizinorg/rizin/blob/master/DEVELOPERS.md for general help on contributing to rizin.