This unit enables learners to focus on the popular Object-Oriented paradigm and associated SOLID principles as exemplified in programming languages such as Java, C++, C# and Python.It includes a strong promotion of the DevSecOps practice; the notion of security being ' hifted to the left' to avoid costly baked-in bugs, encouraging a shared responsibility through the software's lifecycle and its quality assurance processes.Furthermore, it encourages learners to consider modern approaches (and tooling) used when products are designed, written, and then deployed at scale in potentially costly (and high-profile) software engineering projects..