Timothy Leary was an American psychologist, writer, lecturer, and countercultural figure whose career moved from respected personality research to radical advocacy for psychedelic drugs. During the 1950s, he helped develop an influential system for mapping interpersonal behavior. By the middle…

Albert Hofmann was a Swiss chemist whose investigations of medicinal plants produced one of the twentieth century’s most consequential scientific discoveries. While studying compounds derived from ergot, a fungus that grows on rye and other grains, he synthesized lysergic acid…

Edwin A. Locke is an American industrial and organizational psychologist whose research changed the scientific understanding of motivation at work. He is best known for developing goal-setting theory, a framework showing that performance is strongly influenced by the goals people…

Charles Darwin was an English naturalist and geologist whose theory of evolution by natural selection transformed biology and altered humanity’s understanding of its place in nature. Darwin did not originate the general idea that species change over time, but he…

Alan Watts was a British-born writer, speaker, theologian, and interpreter of Asian philosophy who introduced millions of Western readers and listeners to Zen Buddhism, Taoism, Hindu thought, and comparative mysticism. With his resonant voice, playful humor, and gift for metaphor,…

Walter Bradford Cannon was an American physiologist whose research changed how scientists understand digestion, emotion, stress, and the internal regulation of the body. Working at Harvard Medical School during the formative decades of modern physiology, Cannon used new imaging methods…

Roger S. Ulrich is an American environmental psychologist whose research transformed how hospitals, clinics, and other healthcare facilities are designed. Before his work gained attention, medical buildings were commonly evaluated according to technical efficiency, sanitation, equipment needs, and construction costs.…

Kurt Lewin was a German American psychologist whose ideas helped establish modern social psychology, organizational psychology, group dynamics, and action research. At a time when much psychological research isolated individuals from their surroundings, Lewin argued that behavior could be understood…

Charles Duhigg is an American investigative journalist and nonfiction author whose work has made research on behavior accessible to a global audience. Rather than conducting laboratory psychology himself, Duhigg works as a synthesizer and storyteller. He draws from neuroscience, social…

George F. Koob is an American behavioral neuroscientist whose research fundamentally changed how scientists understand addiction. Earlier accounts frequently emphasized the intense pleasure produced by alcohol and other drugs, suggesting that people continued using substances mainly because they wanted to…

Bessel van der Kolk is a Dutch-born American psychiatrist, researcher, and author whose work helped transform the modern understanding of psychological trauma. Beginning with Vietnam veterans in the late 1970s, he studied why terrifying experiences may continue to shape emotion,…

Judith Lewis Herman is an American psychiatrist whose work transformed the understanding of psychological trauma, especially the effects of sexual abuse, domestic violence, captivity, and prolonged interpersonal domination. At a time when the suffering of abused women and children was…