The Nix Package Manager
Rendered book can be found at https://book.divnix.com/
This book is heavily inspired by the rust-lang/book and serves to provide new Nix users a quick introduction to fundamental Nix concepts.
It's recommended to use this resource as a precursor to nix-pills which is much more in-depth on details, but a much longer read.
For a dev environment with mdbook on your shell:
Use nix develop or direnv allow
Run mdbook serve to launch a local webserver hosting the contents
Run mdbook build to build nix-book.