A review of the literature reveals strong evidence for both the mechanical model of disease production (structural) and the neurobiological model (functional). Outdated models which attempt to describe a scientific basis for chiropractic theory are inadequate and indeed harmful to the progress and acceptance of chiropractic. Pragmatic or empirical arguments that "Chiropractic works and that's what counts" have served a useful purpose, but now must be augmented by extant research findings. The "paradigm shift" is on. Research investigators around the world are focusing on the multiple components of the chiropractic subluxation complex (CSC), a definitive, provable clinical entity. No longer can "informed" critics support the accusation that "chiropractic practice is based upon irrational, untenable premises." Only a few more pieces of the puzzle need to be fitted into place to produce the "big picture," i.e., the vertebral column is one of the most neglected vital organs in the human body--the sine qua non of the neurobiomechanical system--which influences every structure and function. Historically, its role in maintaining health has been almost totally ignored and for nearly a century chiropractors have battled against the consequences of this neglect. The scientific community is about to see that chiropractic is leading the way in discovering the "new world" in health care. Past, present and future research is discussed.