Who is Harry Morgan from Darkly Dreaming Dexter and what is their importance?

Harry Morgan is Dexter's foster father and Deborah's father. Harry discovers Dexter at a crime scene and takes him into his home, where he becomes a substitute father and mentor. Harry's care for Dexter includes accepting him for who he is, and advising him to take the safe path, rather than the destructive path. His decisions might be considered questionable.