Point of Inquiry is the radio show and flagship podcast of the Center for Inquiry (CFI), "a think tank promoting science, reason, and secular values in public policy and at the grass roots". Started in 2005, Point of Inquiry has consistently been ranked among the best science podcasts available in iTunes. It has been celebrated for its guests and for the quality of its interviews. Former guests include leading scientists, writers and public intellectuals such as Neil DeGrasse Tyson, Paul Krugman, Lisa Randall, Brian Greene, Oliver Sacks, Susan Jacoby, David Brin and Temple Grandin.