As a recollect reading Bill Ayers was directly responsible, in that he encouraged Obama to write his book and in fact assisted Obama throughout its creation.

Bill Ayers lived closely to Obama in chicago and had a major influence regarding Obama's politics,it just that neither will admit it for the obvious reason, pretty much the same way Rev Wright only played a small part in Obama's life. That's why next to Obama, Cain appears to be a moderate. Its all relative isn't it.