Dart makes it easier for programmers to build structured modern web apps that scale from simple scripts to the largest systems. The Dart Programming Language is an authoritative and rigorous description of the Dart language. Written by Dart spec lead Gilad Bracha, it is designed for computer scientists, advanced students, and experienced software professionals. It is intended to be a readable textbook that introduces the language, its rationale and its philosophy. This guide offers example-rich coverage of both basic programming constructs and the language's most powerful features. Based on the 1.0 release, it offers especially valuable coverage of Dart's innovative approach to reflection, and its actor-style model for asynchronous programming -- two crucial topics that have received insufficient attention in earlier discussions of Dart.