Quotes from book
Extraordinary Popular Delusions and the Madness of Crowds

Extraordinary Popular Delusions and the Madness of Crowds is an early study of crowd psychology by Scottish journalist Charles Mackay, first published in 1841. The book was published in three volumes: "National Delusions", "Peculiar Follies", and "Philosophical Delusions". Mackay was an accomplished teller of stories, though he wrote in a journalistic and somewhat sensational style.

“Credulity is always greatest in times of calamity.”
Extraordinary Popular Delusions and the Madness of Crowds (1841)