This book is a joy to read and remains relevant in the current era of financial boom and bust. Mackay examines animal magnetism, money-mania, tulip-mania, the history of hair and facial hair, the crusades, haunted houses, and much more. Throughout history, the most extraordinary fashions and trends have been followed unthinkingly, and occasionally this crowd fever has overtaken not only a town but a whole country; in some cases much of western Europe was engulfed simultaneously. The ability of some manias to be so far-reaching, and for common sense and intelligence to abandon such large populations seem incredible, though the book is as thought-provoking now as it was when first published in 1852.