In the nineteenth century, studies first began on certain life rhythms or cycles that were later termed "biorhythms". The word biorhythm is a compound of two Greek words, bios and rhythmos, which mean life and a constant or periodic beat. The theory of biorhythms defines and measures three basic and important life cycles in man: the physical, emotional, and intellectual.

Wilhelm Fliess, a highly respected and prominent doctor in Berlin, did pioneer work on biorhythms in the 1890s. Fliess, who had observed 23- and 28-day rhythms in many of his patients, began to collect statistics on the periodic occurrence of fevers, childhood disease, and the susceptibility to disease and death. With these statistics in hand, Fliess believed he had detected rhythms which were fundamental to man's life.

Dr. Fliess later developed two major biorhythm theories: first, that Nature bestows on man "master internal clocks" which begin counting time at birth and continue throughout life; and second, that one of these clocks regulates a 9-3-day cycle influencing man's physical condition and another regulates a 28-day cycle influencing emotions or degree of sensitivity.

A widely read man, Fliess speculated on why these two rhythms should prevail. He believed, much as we do today, that man is essentially bisexual in nature, composed of both male and female elements. Fliess called the 23-day physical cycle the male cycle, since it influenced strength, endurance, and vitality. He considered the 28-day cycle to be representative of the female element in all human beings; it governed sensitivity, intuition, love, and creativity-the entire emotional spectrum.

Subsequent research has reinforced the idea of the 23-day physical and 28-day emotional cycles. Of course, today few would agree with the premise that all physical components are male and all emotional matters female. Instead, both are now considered to be essential characteristics of each sex.

Wilhelm Fliess wrote extensively about the biorhythm theory, but the mathematics and statistics he used to support it were so massive and confusing that few people bothered to closely examine or to understand them. Still, the basic premise of the theory caught on. The idea of periodic rhythms in man created a considerable controversy among his colleagues, one which still exists today. Most scientists have accepted the fact that man's physical and emotional states are in constant flux, but many do not agree that these changes are influenced by regular biological cycles that start at birth.

One of Fliess' contemporaries who kept an open mind to his ideas was Sigmund Freud, a man with extremely revolutionary ideas of his own at the time. Early in his career, Freud showed extreme interest in and admiration for Fliess' theories, and they soon became very close friends. One hundred and eighty-four letters from Freud to Fliess have been published; unfortunately, the replies from Fliess have been lost.

Important ideas tend to spread rapidly in the scientific community. Dr. Hermann Swoboda, Professor of psychology at the University of Vienna, read Fliess' work while still a young man, and by the turn of the century was himself researching, lecturing, and writing on biorhythms. Swoboda, who detected a periodicity in the occurrence of dreams and thinking processes, and in fevers, asthma, heart attacks, and the outbreak of illness, believed his own investigations confirmed Fliess' observations on the 23-day and 28-day cycles. Swoboda contributed to the theory the notion of the "critical" day, when the cycle shifts from high to low or low to high; a day of instability and usually of some stress for most people.

when we seem to have more energy, vitality, and emotional control. There are days when these same feelings are at low ebb. And there are also those days when we react to situations in a totally unexpected way.

There are many people who support the biorhythm theory. Bertram Brown, Director of the National
Institute of Mental Health, has said, "These biorhythms have a lot of validity. They help explain in part everything from having a bad week to exciting scientific things like the varied effects medications have when administered at different times."

Douglas Kelley, a statistician with the National Safety Council, is quoted as saying: "When chemistry was at the state where biorhythm is today, it was called alchemy. But alchemy became chemistry, and within fifty years research may do the same for biorhythm."

On the other side is Colin Pittendrigh, an expert on biological rhythms at Stanford University. The Washington Post quoted him as saying, "I consider this stuff an utter, total, unadulterated fraud. I really know nothing about it because we've been unable to track it down. But I consider anyone who offers to explain my life in terms of 23-day rhythms a numerological nut, just like somebody who wants to explore the rhythms of pig iron price to 11 decimal places."

Against these pros and cons and lacking sufficient clinical methods to prove the theory, an alternative procedure is to apply it to numerous situations and to carefully note the results, rather than to constantly criticize its assumptions. This alternative is recommended to the reader. Numerous opportunities are provided throughout this book for the reader to test the theory. Actually, the situation is similar to accepting or rejecting the daily weather forecast. The forecast can't be proved. But it is too useful and important in the life of an individual to neglect or refuse to accept. Nor is one too concerned if the weather forecast is not completely reliable. I may carry my raincoat tomorrow when, in fact, the sun will shine brightly. However, I still feel rewarded in that I was prepared for the event of rain. I also know the next forecast is quite likely to be valid.

These are not unique circumstances for man. He has always had to choose between the objective and the subjective, that which he can feel versus that which he can sense, fact versus fancy if one pleases. Economic and social men are perfect examples. They cannot act through certainty because proof does not exist for the many actions they follow. Economic man - like biorhythmic man - must be completely informed. Being completely informed is to know all courses of action that are open to him. Against this criteria it is foolhardy, indeed, to completely ignore or refuse to examine the biorhythm theory. "Too stupid to come in out of the rain" is often a result of refusing to observe the forecast of rain. A hasty decision, made now, without regard to another time when mental capabilities may be supposedly keener, is the mark of insensitivity; and irrationality is often the inability or reluctance to observe all factors and possible courses of action available.