Dr. John-Alder is interested in the general area of ecological and evolutionary physiology and endocrinology: the study of functional traits of organisms, their underlying (endocrine) regulation, and the significance of their variation in the natural world. He has investigated organismal energetics, thermal physiology, exercise performance capacities, and growth regulation, and has included studies on thyroidal, gonadal, and adrenal endocrine systems. Henry's general approach crosses traditional levels of biological organization from biochemical to behavioral and includes a blend of laboratory and field research. He stresses the importance of field experiments solidly grounded in natural history.