A couple years ago there was a lot of discussion at American Thinker of Frank Marshal Davis, "Frank" of "Dreams From My Father" who was Obama's mentor as a teen.
Paul Kengor has written a book about Davis called "The Communist".
You can listen to the author interviewed here.
And you should.
I just read of Valerie Jarret: "Her step-father, Vernon Jarrett was associated with Frank Marshall Davis, the youthful Barack Obama's mentor
from age 10 until college - a Chicago Communist Party (USA) member who
moved to Hawaii from Chicago. Frank Marshal Davis is now immortalized
in President Barack Hussein Obama's "autobiography" as "Uncle Frank" --
conveniently with no mention of his last name nor who he was."