I am a historian, specializing in the environmental history of tropical crops, especially coffee. I teach in the history department at the University of Guelph, a vibrant comprehensive university located in the lovely city of Guelph, short drive west of Toronto, Canada. My first book, States of Nature: Science, Agriculture, and Environment, 1760-1940, focused on the expansion of the plant sciences in the Spanish-speaking Caribbean. Since then, I have done research on the environmental history of cacao cultivation, and most recently on the environmental history of coffee cultivation. I have been particularly interested in the impact of crop diseases on these tropical commodities. My latest book is Coffee is Not Forever: A Global History of the Coffee Leaf Rust, a history of one of the most destructive of these diseases, which continues to wreak havoc in the tropics up to the present. Many of my publications are available for free download at my academia.edu website and on my ResearchGate site. I post historical and other images of coffee on my Instagram feed.