Lightning Components Developer Guide

What is the Lightning Component Framework?
What is Salesforce Lightning?
Why Use the Lightning Component Framework?
Components
Events
Open Source Aura Framework
Browser Support Considerations for Lightning Components
My Domain Is Required to Use Lightning Components in Your Salesforce Org
Using the Developer Console
Quick Start
Creating Components
Using Components
Communicating with Events
Creating Apps
Styling Apps
Developing Secure Code
Using JavaScript
Using Apex
Lightning Data Service
Testing Components with Lightning Testing Service
Debugging
Performance
Reference
PDF

What is the Lightning Component Framework?

The Lightning Component framework is a UI framework for developing dynamic web apps for mobile and desktop devices. It’s a modern framework for building single-page applications engineered for growth.

The framework supports partitioned multi-tier component development that bridges the client and server. It uses JavaScript on the client side and Apex on the server side.