[c#] C#: Waiting for all threads to complete

I read the book C# 4.0: The Complete Reference of Herbert Schildt. The author use join to give a solution :

class MyThread
    {
        public int Count;
        public Thread Thrd;
        public MyThread(string name)
        {
            Count = 0;
            Thrd = new Thread(this.Run);
            Thrd.Name = name;
            Thrd.Start();
        }
        // Entry point of thread.
        void Run()
        {
            Console.WriteLine(Thrd.Name + " starting.");
            do
            {
                Thread.Sleep(500);
                Console.WriteLine("In " + Thrd.Name +
                ", Count is " + Count);
                Count++;
            } while (Count < 10);
            Console.WriteLine(Thrd.Name + " terminating.");
        }
    }
    // Use Join() to wait for threads to end.
    class JoinThreads
    {
        static void Main()
        {
            Console.WriteLine("Main thread starting.");
            // Construct three threads.
            MyThread mt1 = new MyThread("Child #1");
            MyThread mt2 = new MyThread("Child #2");
            MyThread mt3 = new MyThread("Child #3");
            mt1.Thrd.Join();
            Console.WriteLine("Child #1 joined.");
            mt2.Thrd.Join();
            Console.WriteLine("Child #2 joined.");
            mt3.Thrd.Join();
            Console.WriteLine("Child #3 joined.");
            Console.WriteLine("Main thread ending.");
            Console.ReadKey();
        }
    }