Question: Can someone explain the concept of sessions in ASP.NET? How do I use them, and how do cookies fit in?

Answer: 
Session is a per-user object for persisting state between HTTP requests. It is good for storing information that you will need on the server to properly serve requests back to the user (e.g. user name, email, etc.).

ASP.NET places a cookie on the client's machine that contains a GUID (in the case of cookieless sessions, this GUID is placed on the URL). This GUID is the user's *session ID*. This identifier is retrieved on each HTTP request from the client by the ASP.NET runtime. Subsequently this identifier is used to rehydrate the user's session data from the session's data-store (either in memory or in the database).
* [ASP.NET State Management Overview](http://msdn.microsoft.com/en-us/library/75x4ha6s.aspx)  

"Use ASP.NET session state to store and retrieve values for a user."  

	+ [Session State Overview](http://msdn.microsoft.com/en-us/library/ms178581.aspx)
		- [Background](http://msdn.microsoft.com/en-us/library/ms178581.aspx#Background)
		- [Code Examples](http://msdn.microsoft.com/en-us/library/ms178581.aspx#CodeExamples)
		- [Class References](http://msdn.microsoft.com/en-us/library/ms178581.aspx#ClassReference)