How do we come to know the world through the things we make? This seminar examines the world around us through the lens of transect science and design. The transect is a visual technique, devised by Alexander von Humboldt and further developed by Patrick Geddes and Ian McHarg, that draws a swath through the landscape—a deep section of an area exposing the habits and habitats of an environment. Transect science and design frames how human activities affect Earth’s interconnected systems—lithosphere, hydrosphere, and atmosphere—and how these activities, in turn, impact both planetary stability and human health. Architects rely on transects to analyze a given terrain to understand better how urban growth can enhance symbiotic relationships with diverse ecosystems. Many environmental researchers use them to understand biodiversity and climate change. The transect concept is also used by public health researchers to characterize how communities interact with aspects of their environment. Transect science and design evolves this concept by integrating technological advancements and cross-disciplinary insights to tackle modern environmental and health challenges. In this course, the transect is more than a transdisciplinary analytical tool: it is a way of seeing and acting in the world. Throughout the semester we collectively examine a series of transects in places as diverse as the Andes and Himalayan Mountains, the Sahel of Africa, archipelagos of the Pacific Ocean, along with transects of Cairo, Beijing, New Delhi, New York, Paris, and Quito.