I was trying to know what nHibernate does before installing it in my pc, when I cam accross the word “OR Mapping” (Object Relational Mapping). I found this link very useful to know a bit about OR Mapping,ObjectSpaces and nHibernate
http://www.dotnetspider.com/tutorials/ObjectSpaces.aspx
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnadonet/html/objectspaces.asp
http://www.theserverside.net/tt/articles/showarticle.tss?id=NHibernate