Walter Dean Myers' father name was Herbert.  At birth, his name was Walter Milton Myers.  Yet, at birth Myers was given to a man named Herbert Dean, who along with his wife, Florence, raised the boy.  Walter Dean Myers does not know why he was given up, but given the fact that Herbert Dean raised him, we can attribute the status of "father" to him.  It is interesting because in so many of his novels, characters explore similar questions of identity as this, in terms of why they are a certain way and how they understand reality as a result of their experience as a child.  Certainly, the presence of Herbert Dean in the author's life might be the reason why ended up taking the name "Walter Dean Myers" in recognition of Herbert Dean, who assumed the role of father in his life.