A top-selling new book examines one of President Obama's mentors, who happened to be a card-carrying communist and was listed on the FBI's "Security Index" during the Cold War with the Soviet Union.

The book is called, The Communist, Frank Marshall Davis: The Untold Story of Barack Obama's Mentor.

Author Paul Kengor explained to CBN News that even though many people don't recognize his name, Davis played an important role in Obama's upbringing.

"The grandfather, Stanley Dunham actually was searching for a black male father figure, mentor for his grandson, because Obama didn't have one because of his biological father. And so, of all people, Stanley Dunham picked Frank Marshall Davis," Kengor said.

"I found Davis just constantly bashing General Motors, bashing Wall Street, bashing the rich and millionaires and Republican tax cuts, favoring redistribution of wealth to public works projects to get America out of a great depression," Kengor explained.

"Calling for taxpayer funding of universal health care - all kind of things that just sound hauntingly familiar to what Obama has said or done as president today," he said.

Kengor said he is not suggesting President Obama is a communist. He's simply offering a portrait of a man Obama has referenced as having an influence on his life.