NHibernate is a popular, mature, open source object / relational mapper (ORM) based on Java's Hibernate project. ORMs, such as LINQ to SQL, Entity Framework, and NHibernate, translate between the database's relational model of tables, columns, and keys to the application's object model of classes and properties.

The NHibernate homepage, http://NHForge.org, contains blog posts, a wiki, the complete reference documentation, and a bug tracker. Support is available through the very active nhusers Google group at http://groups.google.com/group/nhusers. The NHibernate source code is hosted on SourceForge at http://sourceforge.net/projects/nhibernate/. Precompiled binaries of NHibernate releases are also available on SourceForge.