Client-Side Storage refers to the practice of storing data directly on a user's device, such as a computer or smartphone, rather than on a remote server. This allows web applications to save information like user preferences, session data, or offline content, enhancing the user experience by making it faster and more responsive. Common methods of Client-Side Storage include Cookies, Local Storage, and Session Storage. Each method has its own characteristics, such as storage capacity and data persistence, allowing developers to choose the best option based on their application's needs.