This document introduces Salesforce DX, a set of tools and processes that allow developers to use source-driven development practices for building on the Salesforce platform. It discusses how Salesforce DX enables principles of modern software delivery like source-driven development, team collaboration, continuous integration and delivery. It also summarizes how Salesforce DX provides tools and processes to improve the developer experience across the application lifecycle from planning to releasing code. Finally, it provides instructions on getting started with Salesforce DX.