Stephen King Dark Tower series

Now they exist in different worlds, paradoxically sharing memories. Roland, Susannah and Eddie must try to draw Jake into Mid-World then follow the Path of the Beam through an urban waste land to the Dark Tower. Pursued by the Ageless Stranger, Roland and his friends cross a desert of damnation in this macabre new world as revelations begin to unfold about who - and what - is driving him forward.