Two-color offset window card bearing a portrait of Hellstrom the mind reader and a portrait of Howard Thurston who was reportedly mystified by Hellstrom's "powers." Light toning in margins, pinholes, bottom edge trimmed. Hellstrom perfected the art of muscle reading (the ability to determine a subject's thoughts based on interpretations of subtle involuntary responses to speech and other stimuli) to such a degree that the technique was later renamed, and is now commonly known as, Hellstromism.