• Rust is the first industry-supported programming language to overcome the longstanding tradeoff between the safety guarantees of higher-level languages (like Java) and the control over resource management provided by lower-level "systems programming" languages (like C and C++). • It tackles this challenge using a strong type system based on the ideas of ownership and borrowing, which statically prohibits the mutation of shared state. This approach enables many common systems programming pitfalls to be detected at compile time. • There are a number of data types whose implementations fundamentally depend on shared mutable state and thus cannot be typechecked according to Rust’s strict ownership discipline. To support such data types, Rust embraces the judicious use of unsafe code encapsulated within safe APIs. • The proof technique of semantic type soundness, together with advances in separation logic and machine-checked proof, has enabled us to begin building rigorous formal foundations for Rust as part of the RustBelt project.