Healing Codes for the Biological Apocalypse by Dr. Leonard Horowitz and Joseph Barber (often associated with Dr. Joseph Puleo) is a 1999 book that presents a combination of spiritual, biblical, and alternative health strategies designed to help humanity survive what the authors describe as a looming "biological apocalypse". The book, which is considered a seminal text in the study of Solfeggio frequencies, argues that modern society faces engineered plagues, famine, and electromagnetic threats. The book serves as a, "guide to surviving global catastrophes and plagues by decoding ancient biblical knowledge and healing codes". It is often credited with prompting a, "revolution in the music and natural healing industries" by highlighting the power of sound in healing.