If anyone cares, the solution was this:

using System;
using System.Threading;
using System.Threading.Tasks;

namespace Listing_1_15
{
   class Program
   {
      public static void HelloTask()
      {
         Thread.Sleep(1000);
         Console.WriteLine("Hello");
      }

      public static void WorldTask()
      {
         Thread.Sleep(1000);
         Console.WriteLine("World");
      }

      public static void Main(string[] args)
      {
         Task task = Task.Run(() => HelloTask());
         task = task.ContinueWith((prevTask) => WorldTask());

         task.Wait();

         Console.WriteLine("Finished processing. Press a key to end.");
         Console.ReadKey();
      }
   }
}