The document discusses the need for a new UI library called Next Generation UI that addresses issues with existing libraries like jQuery plugins, YUI, and ExtJs. It highlights pain points like changing web standards, lack of MVC support, large file sizes and speed issues. It then provides overviews and examples of widgets like layouts, grids, trees, tabs, popups and toolbars that the new library aims to provide with a consistent API, small file size and fast performance while supporting customization.