The Rust Book

 https://doc.rust-lang.org/book/ch00-00-introduction.html

There is another book called "Rust By Example" 

(both these books can be accessed by typing "rustup doc")

Systems Programming - Low-Level Academy

https://lowlvl.org

an explorable systems programming course that uses #rustlang and #webassembly for interactive playgrounds and visualisation. It starts with network programming, but it will be expanded to more topics!