Ed Armston-Sheret returns to Time to Eat the Dogs to talk about British geographical expeditions and the labor that made them possible, specifically the labor of local peoples that is frequently omitted from explorer accounts. Armston-Sheret is a Fellow at the Institute of Historical Research, University of London. He's the author of On the Backs of Others: Rethinking the History of British Geographical Exploration.

David Kaiser talks about the history of twentieth-century physics and the forces that have shaped it as a scientific discipline. Kaiser is a Professor of the History of Science at the Massachusetts Institute of Technology where he is also a Professor of Physics. He's the author of Quantum Legacies: Dispatches from an Uncertain World.

Dane Kennedy talks about Mungo Park's troubled expeditions in West Africa and the rescue expeditions that set off to find him. Kennedy is an emeritus professor of history and international affairs at George Washington University. He has written eight books including Mungo Park's Ghost: The Haunted Hubris of British Explorers in Nineteenth-Century Africa

Gerald Easter and Mara Vorhees talk about the voyage of the Vrouw Maria and the long quest to find the ship under the waters of the Archipelago Sea off the coast of Finland. Easter is a professor of history at Boston College. Vorhees is a travel writer for Lonely Planet with an expertise in Russia, New England, and Central America. They are the authors of The Tsarina's Lost Treasure: Catherine the Great, a Golden Age Masterpiece, and a Legendary Shipwreck.

Adam Higginbotham talks about the history of the Space Shuttle program and the decisions that made the Challenger explosion almost inevitable. Higgenbotham is a journalist and contributing writer for the New Yorker, Wired, and the New York Times. His book Midnight in Chernobyl won the Andrew Carnegie Medal for Excellence in Non-Fiction and was selected as one of the 10 best books of 2019 by the New York Times. He discusses his new book Challenger: A True Story of Heroism and Disaster on the Edge of Space.

Catarina Madruga talks about Portuguese exploration in the nineteenth century as European powers made plans to conquer Africa and colonize its peoples. Madruga is a post-doctoral researcher at the Natural History Museum of Berlin. She's the author of "Expert at a Distance: Barbosa du Bocage and the Production of Scientific Knowledge on Africa," Journal for the History of Science and Technology, 11, 57-74.

Historian of science Jeffery Mathias talks about scientific experiments in isolation during the Cold War. Mathias is the author of the Ph.D dissertation, "An Empire of Solitude: Isolation and the Cold War Sciences of the Mind."

Alexandre Simon-Ekeland talks about explorers, the Polar Regions, and the French imagination. Simon-Ekeland recently completed his doctoral dissertation at the University of Oslo. He is the author of Making French Polar Exploration, 1860s-1930s.