In this chapter of the course, you'll learn about Object-oriented Programming (OOPHP). OOPHP encompasses a lot of concepts that will help you write code more efficiently and reliably, such as creating classes, defining properties & methods, using parameters & arguments, writing constructors, type declarations & hints, and promoted properties. Here's an overview of each concept to help you get started:

• Classes: Used to create & define objects
• Properties: Variables that belong to the object
• Methods: Function used to add functionality to the object
• Parameters & Arguments: Variables used when defining methods or passing data to the object
• Constructors: Special type of Method called behind-the-scenes when an object is created
• Type Declarations & Hints: Used to keep code consistent & predictable
• Promoted Properties: Streamlines code needed to set property values in the constructor

Understanding OOPHP concepts and applying them to your code will help increase your efficiency, and is an essential part of writing reliable & efficient code.