In this chapter, we explore three key aspects of constructing modern code that you will use:

1. Languages: Much like in everyday life, language is the vehicle with which we express ourselves. In software engineering, different languages are better at expressing different concepts and influence how their resultant software is structured.
2. Asynchrony: Allowing code to be run in different orders and threads allows optimization and smooth user experiences.
3. Assertions: How to write tests in a way that verifies what is important, but nothing more.

4. RESTful APIs: Bridging systems using REST principles, including resource-based architecture, HTTP verbs, and statelessness. RESTful APIs facilitate seamless communication between applications.

These topics empower software engineers to create efficient, maintainable, and interconnected systems.