The document provides a tutorial on implementing custom paging in GridView using ASP.NET 4.5, enhancing performance by displaying only the relevant data per page index, rather than binding the complete data source. Key features include the properties 'VirtualItemCount' and 'AllowCustomPaging', which enable the GridView to manage paging while reducing application overhead. The document details the setup process through a series of steps, including code snippets for page setup, data binding, and database interaction using stored procedures.