“Thoughts Are Things”
The modern writer who most decisively advocated the health-and-wealth-building powers of the mind is an American journalist, essayist, and mystic troubadour whose legacy, while etched across motivational literature, has faded like pencil on a water-logged page: Prentice Mulford (1834–1891).
In a sense, Mulford’s work forged the missing link in the transition of New Thought—an umbrella term for America’s positive-mind philosophies — from a predominantly health-based outlook, often called “mind cure,” into an all-purpose metaphysical system for happiness and success.
Indeed, Mulford’s tracts of the late 1880s and early 1890s mark the critical moment when New Thought’s abstruse, 19th century tone fell away; from Mulford’s writing emerged a remarkably modern and appealing vernacular, which won a vastly expanded, enduring audience for mind-power metaphysics — if not for the author himself.
In some regards, Mulford was the most influential of all early self-improvement writers. His personal journey itself proved an exercise in repeat transformations — and, toward its end, the pioneering writer-seeker struggled to live by the principles whose modern form he devised.
Mulford was born to a wealthy Long Island family in 1834. His father’s early death cut short his fortunes. At age 15, Mulford was forced to leave school to support his mother and three sisters by running the family’s sole remaining property: a four-story hotel in Sag Harbor, Long Island. In about four years the hotel failed. Day labor was too dull and dead-end a prospect for the restless and curious young man. He instead went to sea, joining the last leg of Sag Harbor’s whaling industry. 
By the late 1850s, with whaling in decline, Mulford found himself stranded in San Francisco. With the Gold Rush booming, he took up life as a prospector, working in mining camps among other migratory or displaced men. It was a punishing daily routine spent bending over, digging and panning. American readers were hungry for news about prospecting, which was heavily romanticized at the time.  Although Mulford hadn’t yet set his mind on becoming a writer, in late 1861 he began producing wry newspaper…