We spent an hour with Koch at his office in Wichita. Here's the full conversation.

Charles Koch's company won't ask applicants if they've been convicted of a crime.

A byproduct of refining gasoline clouds the skies of a South Side Chicago neighborhood.

Ads target swing states of Ohio and Virginia.

Koch-backed nonprofit hits Obama on 'failing agenda'

Conservative political nonprofit continue to blanket airwaves with attack ads in Senate races.

Patriot Majority USA kicks off long-term campaign targeting billionaire Koch brothers