Stephen Bannon , President Donald Trumps chief strategist and the driving force behind the administrations controversial ban on travelers from seven Muslim-majority countries, has a favorite metaphor he uses to describe the largest refugee crisis in human history.

Its been almost a Camp of the Saints-type invasion into Central and then Western and Northern Europe, he said in October 2015 .

The whole thing in Europe is all about immigration, he said in January 2016 . Its a global issue today this kind of global Camp of the Saints.

Its not a migration, he said later that January . Its really an invasion. I call it the Camp of the Saints.

When we first started talking about this a year ago, he said in April 2016 , we called it the Camp of the Saints. ... I mean, this is Camp of the Saints, isnt it?

Bannon has agitated for a host of anti-immigrant measures. In his previous role as executive chairman of the right-wing news site Breitbart which he called a platform for the alt-right, the online movement of white nationalists he made anti-immigrant and anti-Muslim news a focus.

But the top Trump aides repeated references to The Camp of the Saints, an obscure 1973 novel by French author Jean Raspail, reveal even more about how he understands the world. The book is a cult favorite on the far right, yet its never found a wider audience. Theres a good reason for that: Its breathtakingly racist.

[This book is] racist in the literal sense of the term. It uses race as the main characterization of characters, said Ccile Alduy, professor of French at Stanford University and an expert on the contemporary French far right . It describes the takeover of Europe by waves of immigrants that wash ashore like the plague.

The book, she said, reframes everything as the fight to death between races.

Upon the novels release in the United States in 1975, the influential book review magazine Kirkus Reviews pulled no punches: The publishers are presenting The Camp of the Saints as a major event, and it probably is, in much the same sense that Mein Kampf was a major event.

Linda Chavez, a Republican commentator who has worked for GOP presidents from Ronald Reagan to George W. Bush but opposed Trumps election, also reviewed the book back then. Forty years later, she hasnt forgotten it.

It is really shockingly racist, Chavez told The Huffington Post, and to have the counselor to the president see this as one of his touchstones, I think, says volumes about his attitude.