Help Needed With This Query

i have marked in bold the query in question ..whch gives me the the runtime error mentioned at the below , i double checked everything all the table names and the field names are correct so whats the problem  , please anyone??
im really stumped!
 
  if (Radio_Btn_Book.Checked == true)
        {
            string book_query = "update Issue_Book_Reserve I set I.Issue_Book_Reserve_state  = 1 where I.Book_Id = Books.Book_Id and Books.Book_Name = '" + Session["Book_name"].ToString()+"'";

            SqlCommand Cmd_book = new SqlCommand(book_query, con);
           
            con.Open();
            Cmd_book.ExecuteNonQuery();
            con.Close();          
        }
ERROR: 
The column prefix 'Books' does not match with a table name or alias name used in the query.
The column prefix 'Books' does not match with a table name or alias name used in the query.