The document discusses Android Data Binding, which is an official Google library that allows binding UI components in XML layouts to data sources in code. It was introduced in 2015 and is currently in version 1.0-rc4. The document provides examples of using Data Binding to avoid findViewById(), bind views to models, include layouts, use expressions, handle null values, create custom bindings, and convert between types. It recommends references for further reading on Data Binding.