An 18th century quack "De Wonderdokter Fop" with Dutch text, illustrated by Hermann van der Moolen. "Ik ben de wonderdokter fop, De wereld door bekend. In heel de wereld leeft er geen Zoo'n hooggeleerde vent." (I'm the miracle doctor, The world by known. Throughout the world lives no such a highly educated guy.) Quackery is the promotion of unproven or fraudulent medical practices. Random House Dictionary describes a "quack" as a "fraudulent or ignorant pretender to medical skill" or "a person who pretends, professionally or publicly, to have skill, knowledge, or qualifications he or she does not possess; a charlatan".