With Insomnia, King introduces us to the big bad of his multiverse, The Crimson King.  He's a character whose legend will cast many of Stephen King's future works in a scarlet shadow.  This bonus episode analyzes the character as he's presented here in contrast to when we see him in the Dark Tower series.  

Also in this episode, I place the Insomnia itself into context of the greater Dark Tower series as well as Patrick Danville.  

So if you've completed your journey to the Tower, feel free to enter the Court of the Crimson King!