Guest Sam White from Ohio State University makes the convincing argument that environmental and climactic factors are as influential in human history as economic, social, political, and cultural factors.

Guest Karl Hagstrom Miller helps us understand how popular music came to be segregated as artists negotiated the restrictions known as the "Jim Crow" laws in the late 19th and 20th centuries.

Guest Daina Ramey Berry she discusses teaching the "senses of slavery," a teaching tool that taps into the senses in order to connect to one of the most important eras in US history and bring it to the present.

Guest Jacqueline Jones, one of the foremost experts on the history of racial history in the United States, helps us understand race and race relations by exposing some of its astonishing paradoxes from the earliest day to Obama's America.

Guest Seth Garfield shows how a little-known chapter of World War II history illuminates the ways outsiders’ understandings of the nature of the Amazon have evolved over the course of the latter half of the twentieth century.

Guest Robert Olwell describes the Royal Proclamation of 1763, its effects on the history of colonial North America, and ponders whether it is really the smoking gun that caused the American Revolution as some have claimed.

Guest Chris Dietrich explains the origins of the oil crisis and the ways it shifted international relations in its wake.

Guest Mary Neuburger walks us through current historical thinking about the five hundred year legacy of Ottoman rule in southeastern Europe, and gives us an alternate explanation for the turbulence of the 19th and 20th centuries.

Guest Joseph Parrott helps us understand the system of "separateness" that dominated the lives of South Africans of all races for so long, and introduces us to the key organizations and players that fought against it and finally dismantled it.

Guest Sahar F. Aziz helps us understand the political earthquakes in Egypt's bumpy transition from authoritarian rule to what comes next, and sheds light on what it might take for the country to arrive at the democracy its people demanded in the streets.