Joseph Puleo lived and worked as a naturopath and herbalist in the small town of Clark Fork, Idaho, and by his own later account began exploring what he took to be a hidden numerical structure in the Bible during the 1970s. Applying a Pythagorean method of reducing multi-digit numbers to single digits, he worked through the seventh chapter of the Book of Numbers, a passage listing repetitive tribal offerings, and reported finding a repeating six-step pattern that he mapped onto six sound frequencies: 396, 417, 528, 639, 741 and 852 Hz. He shared the finding quietly within alternative health circles for years, at times under a pseudonym, before it reached a wider public.
That wider public arrived through Leonard Horowitz, a public health author who took up Puleo's numerological derivation and, with Puleo as co-author, published it in 1999 as Healing Codes for the Biological Apocalypse, presenting the six tones as an ancient, once-suppressed musical and healing system rather than the recent numerological exercise Puleo himself had actually performed. The book credits Puleo directly as the discoverer of the frequencies and Horowitz as the one who framed and popularized their supposed historical and medical significance, a division of labor the sourcing for the claim has never fully separated in public retelling since.