The session state is used to maintain the session of each user throughout the application. Session allows information to be stored in one page and access in another page and support any type of object.Whenever user enters into website new session id will generate for that user. This session Id will delete when he leave from that application. If he enters again he will get new session Id. Eg. Session["FirstName"] = txtfName.Text;

it manages the users information with in web server.session is nothing but duration.information can be stored through cookies.