rCore-Tutorial-Book-v3 is the official book for the third version of the rCore OS tutorial series, a comprehensive educational resource for learning operating system development using the Rust programming language. Targeted at the RISC-V architecture, this tutorial guides learners step-by-step through building a minimal, safe, and modern OS kernel from scratch. It is written in Markdown and powered by mdBook, making it easy to read, navigate, and contribute to. The book combines theoretical explanations with practical exercises, allowing students and enthusiasts to understand core OS concepts like bootstrapping, memory management, and process scheduling through hands-on implementation.