Charles-Marie Gustave Le Bon was a French polymath whose areas of interest included anthropology, psychology, sociology, medicine, invention, and physics. He is best known for his 1895 work The Crowd: A Study of the Popular Mind, which is considered one of the seminal works of crowd psychology. A native of Nogent-le-Rotrou, Le Bon qualified as a doctor of medicine at the University of Paris in 1866. He opted against the formal practice of medicine as a physician, instead beginning his writing career the same year of his graduation. He published a number of medical articles and books before joining the French Army after the outbreak of the Franco-Prussian War. Defeat in the war coupled with being a first-hand witness to the Paris Commune of 1871 strongly shaped Le Bon's worldview. He then travelled widely, touring Europe, Asia and North Africa. He analysed the peoples and the civilisations he encountered under the umbrella of the nascent field of anthropology, developing an essentialist view of humanity, and invented a portable cephalometer during his travels.