Web Forms :: How To Share Variable From One Webpage To Another

I have a problem,related to sharing variable between 2 pages.i am using session for it but it does not work,below is my code

firstpage.aspx;
protectedvoid LinkButton7_Click(object sender, EventArgs e){
Session["catagory"] = LinkButton7.Text;
Response.Redirect("secondpage.aspx");
}

secondpage.aspx;
protected
void Page_Load(object sender, EventArgs e) {
Class1.connection();
// string catagory = Convert.ToString( Request.QueryString["catagory"]);// string month1 = Request.QueryString["monthtest"];

[Code] ....

But on secondpage.aspx  i am not able to access value of session["catagory"] that means it have stored null value automatically. How I will access it....