"Memoirs of Extraordinary Popular Delusions — Volume 3" by Charles Mackay is a volume first published in 1841. This final volume explores humanity's philosophical delusions, focusing on the misguided pursuits of alchemists seeking to transform base metals into gold. Mackay examines how practitioners and their noble sponsors fell prey to elaborate deceptions and self-delusion. The volume also investigates fortune-telling and magnetisers who claimed to cure diseases through imagination, revealing the persistent human susceptibility to pseudoscientific beliefs and supernatural explanations across centuries. (This is an automatically generated summary.)