Trust in the safety and security of software systems is increasingly important with the use of software in systems where failure or sabotage can lead to loss of life or be very expensive (this includes medical and financial applications as well as software used for power grids, amss transport systems, and security infrastructure). This course covers language based safety engineering techniques advanced type systems, specification-based test generators, domain-specific languages, and prototyping for high-assurance. It demonstrates via concrete examples, including security infrastructure software, how modern functional languages are used to achieve high assurance, and conveys hands-on experience via practical assignments.