Historically, the means by which a society accomplishes work – the type of energy it employs, from steam power to nuclear power – is one of its defining characteristics and most significant concerns. On a smaller scale (and more important to us because of this book's subject matter), the way a particular body uses energy, along with the amount of energy that body innately possesses, is one of its essential characteristics.

The perception of one's own energy links to one's overall sense of well-being, both physical and mental. Even if someone is not in a recognizable state of ill health, if that person's energy is low or somehow off, he or she won't feel lively and won't be satisfied with the business of living.

In the Western world, although we know our own energy as the something we have plenty of when we are able to move our body with ease, work hard, think clearly, and play pleasurably, that something is not especially well defined. Therefore, for the most part, we conduct our relationship with our energy on a subconscious level.

We accept that we have a specific, innate measure and quality of energy that allows us, on a typical day, to achieve particular amounts of certain tasks. We work in the garden for three hours before exhaustion and backache set in; ride a bike on a flat surface for four hours (as opposed to up a steep hill for three minutes); study Italian for one hour; engage in an emotional disagreement for 17 minutes.

We also recognize not many days are typical and that our energy fluctuates a great deal, sometimes for no apparent reason. At other times, we are affected when certain variables are introduced, such as joy versus tedium, water as opposed to coffee, a good night's rest or the lack of it, a hilarious companion compared to a judgmental one, a bowl of organic steamed vegetables or a block of red meat, a pleasant surprise or a disappointment, or a shot of wheatgrass instead of a shot of tequila. For the most part, we understand that energy comes and goes.

We are disappointed when we should have it, but don't and delighted when we shouldn't have it, but do. Sometimes we spend it wantonly until it is entirely gone. At other times, we attempt to save it. For most of us in the West, in spite of all the subliminal attention we pay to our sense of our energy, our conscious belief is that the real workings of our bodies are governed by mechanical and chemical processes ...we neither understand nor believe we can influence to any great extent.

The body as a machine has mesmerized Western doctors (and their patients) since Isaac Newton's time. In part, this view prevails because it is easier to apply the same laws to living beings and non-living matter.

As orthopedic surgeon and groundbreaking research scientist Robert O. Becker (The Body Electric) has said of himself and his cohorts, "Of course, we all knew that life was more a process than a structure, but we tended to forget this, because a structure was so much easier to study."

Still, throughout history, many notable scientists, philosophers and artists have focused their minds less on the static structures of living matter and more on the vital but enigmatic processes of life.

It wasn't until the late 19th century that studying life as a process and not a machine became formally known as vitalism in the West. Aristotle claimed that neither physical nor chemical forces shape and support matter and that mechanism cannot explain life. He called the animating force entelecheia.

Many distinguished scientists and philosophers further developed this idea, including German physician Samuel Hahnemann, whose "like cures like" became the basis for homeopathy and Nobel-prize-winning French philosopher Henri Bergson, who called the force the "élan vital."

Biologist T. H. Huxley, a great supporter of Darwin's theory of evolution, likened the non-material element to great art.

"In traveling from one end to the other of the scale of life," Huxley said, "we are taught one lesson, that living nature is not a mechanism but a poem; not a mere rough engine-house for the due keeping of pleasure and pain machines, but a palace whose foundations, indeed, are laid on the strictest and safest mechanical principles, but whose superstructure is a manifestation of the highest and noblest art."

Vitalism as a formal scientific movement and intellectual construct fell far out of favor shortly after the turn of the 20th century, but not before one of its last great champions, respected German experimental embryologist Hans Driesch (1867–1941), helped pave the way for today's latter-day vitalists.

In one experiment, Driesch pinched a two-celled sea urchin embryo in half, whereupon each cell developed into a whole, if smallish, sea urchin rather than the expected half-formed urchin. At the time, regeneration of this sort was surprising, to say the least, and led Driesch to believe that living matter must follow a kind of logic outside then-known physical laws.

A short time later, in 1905, Albert Einstein published his well-known equation, E=mc², with its radical suggestion that energy and matter are twin facets of the same universal substance, shedding yet more light on the quintessence of life. Since then, but especially since the 1960s, people from an even wider variety of disciplines including philosophy, physics, biochemistry, physiology, mysticism and anthropology, have acknowledged the distinction between organic and inorganic matter, exploring new ideas about the relationship of matter and energy. In current pop culture, "May the Force be with you" from Star Wars is perhaps the most well known expression of today's vitalism.

In today's sometimes bafflingly diverse world of complementary and alternative medicine, a belief in vitalism (although the movement, as such, is dead) is one of the key unifying principles. It is set apart from orthodox Western medicine, which simply gives this non-material element or vital force the label energy.

Although somewhat new to the West, energy concepts have an ancient basis in the East. Chinese traditions call this vital energy Qi or Ch'i.

Dr. Richard Gerber, in his seminal book Vibrational Medicine, describes ch'i as a "substance that flows from the environment into the body… an energy of both nutritive and cellular-organizational characteristics which supersede the energetic contributions of ingested food and air."

In Chinese traditions, Ch'i enters the body by way of tiny, distinct gateways on the surface of the skin – the acupuncture points – and flows along the meridian system to the body's organs, providing life's essential energy.

In the ancient Indian system of healing known as Ayurveda, this subtle, life-sustaining energy is prana, and enters our bodies as we breathe.

According to Tantra, a tradition closely linked to Ayurveda, the body possesses seven whirling centers of concentrated energy known as chakras, from the Sanskrit meaning wheels. Like the meridians, the chakras take in high-frequency subtle energies and transform them into a serviceable form.

An aura, on the other hand, is a shell of energy or an energy field that emanates from and surrounds the body. It both shields the body from energies with which it does not resonate, and welcomes energies with which it does.

According to Robert O. Becker, before the discovery of penicillin and other antibiotics, "medicine had been an art. The masterpiece – a cure – resulted from the patient's will combined with the physician's intuition and skill in using remedies culled from millennia of observant trial and error."

In the last two centuries, medicine more and more has come to be a science, or more accurately the application of one science, namely biochemistry.

Medical techniques have come to be tested as much against current concepts in biochemistry as against their empirical results. Techniques that don't fit such chemical concepts – even if they work – have been abandoned as pseudoscientific or downright fraudulent.

Drugs became the best or only valid treatments for all ailments. Prevention, nutrition, exercise, lifestyle, the patient's physical and mental uniqueness, environmental pollutants – all were glossed over.

In the 1950s, one might travel through several towns before coming across a health-food store or a naturopath, much further in the vast middle of the country, and one might travel over an ocean before finding someone who even knew what acupuncture was.

In 1962, California's newly opened Esalen Institute afforded a local forum for the exploration of what Aldous Huxley called the "human potential."

In 1972, Richard Nixon visited China for the first time. It was in no small part as a result of Nixon's visit that acupuncture and related concepts of energy flow and blockages began to reach a larger, more diverse segment of Western society.

Meanwhile, in the world of science, quantum physicists were introducing the general populace to the idea that the matter we are able to perceive with our senses is but a minuscule part of the observable cosmos.

In 1791, Italian physician and anatomy professor Luigi Galvani announced to the Academy of Science in Bologna that the mysterious vital force – the élan vital – was electrical.

Throughout the 1800s, especially in Western Europe, researchers continued to look for evidence of those properties.

While working at Yale in the 1930s, biochemist Harold Saxton Burr discovered the presence of electric fields around many different types of organisms, from worms to humans.

In 1939, French engineer Georges Lakhovsky published The Secret of Life, in which he detailed his extensive experiments with cancerous geraniums that ultimately led to his conclusion that living cells possess characteristics not unlike electronic circuits.

Meanwhile, Nobel-Prize-winning Hungarian biochemist Albert Szent-Gyorgyi, the discoverer of Vitamin C, speculated that the molecular structures of the body could support semi-conduction.

Brilliant research pioneered by Becker in the 1960s revealed a system of electrical currents within the nervous system that mediate tissue repair and regeneration.

At the Karolinska Institute in Stockholm, head radiologist Dr. Björn Nordenström discovered what he believed to be an electrical circulatory system in the body.

There is a large degree of certainty that the endogenous electrical activity of the body, at the very least, can indicate a specific pathological process, and that it can act as an initiator of growth and of healing processes.

Even in conventional Western medicine, the measurable electrical activity of the body has been used for many years for both diagnostic and monitoring purposes (i.e. EEG, EKG, X-ray, and MRI).

Electrical activity is used for treatment purposes (i.e. radiation to treat cancer, electromagnetic fields to stimulate fracture healing, and the application of direct current for pain relief).

Traditional science, for instance, continues for the most part to ignore the subtle energy systems of the body, in spite of the well-documented fact that the electrical activity of the acupuncture points shows less resistance and greater conductivity, differing considerably from that of the surrounding skin.

Furthermore, the SQUID apparatus – an extremely sensitive magnetic-field detector invented by solid-state physicist Brian Josephson in 1964 – measures subtle energy fields.

According to Robert O. Becker:

"The breakthroughs against infections convinced the (medical) profession of its own infallibility and quickly ossified its beliefs into dogma. Life processes that were inexplicable according to current biochemistry have been either ignored or misinterpreted."

Western society is slowly changing and expanding to include a wider view of what is available in the different realms of self-care. People are exercising their right to explore and create. They are exercising their right to choose.