This document discusses ASP.NET Dynamic Data, which is a framework that allows developers to easily create data-driven web applications by automatically discovering the data model at runtime. It summarizes the key benefits of Dynamic Data such as increased productivity through scaffolding and minimal code. The document then outlines what is new in Dynamic Data Preview 4, including improvements to filtering, support for inheritance and many-to-many relationships, and new controls. It also provides instructions on starting a new project with Dynamic Data Preview 4.