This article is more than 2 years old.

August 1, 2016 This article is more than 2 years old.

At a super secretive meeting this weekend, conservative American tycoons are boning up on classic books about capitalism and fossil fuels.

From Saturday through today (August 1), industrialist billionaires David and Charles Koch are hosting a retreat in Colorado Springs, Colorado. The roughly 400 select donors to Koch-approved political organizations gather bi-annually to discuss policy efforts and hear from guest politicians.

Paul Ryan, speaker of the US House of Representatives, addressed the retreat this year, reports CNN. Charles Koch said he would “certainly” not be supporting Hillary Clinton, nor funding Donald Trump. According to Time, the group has a budget of $750 million this year.

Between panel discussions, attendees were invited to catch up on their reading, according to a tweet from CNN’s Teddy Schleifer. A photo from him shows book request cards for 48 titles about politics, freedom, business, and fossil fuels.

Books that attendees can request to have sent to them include:

Abundance: The Future is Better Than You Think, by Peter Diamandis and Steven Kotler (2012)

Peter Diamandis, cofounder of Singularity University, and journalist Steven Kotler lay out their optimism about the era of abundance, in which all people will be able to have their basic needs met.

Peter Diamandis, cofounder of Singularity University, and journalist Steven Kotler lay out their optimism about the era of abundance, in which all people will be able to have their basic needs met. The Myth of the Robber Barons: A New Look at the Rise of Big Business in America, by Burton W. Folsom, Jr. (1987)

Historian Burton W. Folsom, Jr. defends “market entrepreneurs” like Cornelius Vanderbilt and John D. Rockefeller, who he believes are wrongly criticized as ”robber barons.”

Historian Burton W. Folsom, Jr. defends “market entrepreneurs” like Cornelius Vanderbilt and John D. Rockefeller, who he believes are wrongly criticized as ”robber barons.” Superpower: Three Choices for America’s Role in the World, by Ian Bremmer (2015)

Writer and political risk expert Ian Bremmer outlines his criticism of American political strategy (or lack thereof), and offers three possibilities for the US’s future role in the world.

Writer and political risk expert Ian Bremmer outlines his criticism of American political strategy (or lack thereof), and offers three possibilities for the US’s future role in the world. My Bondage and My Freedom, by Frederick Douglass (1855)

The second volume of abolitionist Frederick Douglass’s autobiography, in which he recounts his journey from slave to freeman and condemns the system of slavery.

The second volume of abolitionist Frederick Douglass’s autobiography, in which he recounts his journey from slave to freeman and condemns the system of slavery. Fueling Freedom: Exposing the Mad War on Energy, by Stephen Moore and Kathleen Hartnett White (2016)

Economics writer Stephen Moore and energy expert Kathleen Hartnett White ”make an unapologetic case for fossil fuels.”

Here’s the book list in full: