Functional Specification is a comprehensive document that provides detailed requirements for a system or product from the user's perspective. Coursera's Functional Specification catalogue teaches you how to articulate system behaviors, interfaces, and performance criteria. You'll learn to draft precise and clear requirements, ascertain necessary inputs and expected outputs, and define system interactions and constraints. Through this, you'll equip yourself with the essential tools to communicate effectively with stakeholders, ensure product alignment with user needs, and create a roadmap for product design and development.