Neurologist Lombard and preventive medicine speaker Renna argue that we are all in a state of chemical imbalance. The authors' premise is that people who are too warm need more of the cooling neurotransmitter serotonin, while people who are too cool need more dopamine. Deficiencies of either chemical lead to certain personality characteristics and are even affiliated with medical conditions such as heart disease. People who are too warm are often restless and angry, while those who are too cool are often fatigued and anxious. As the authors explain, "When we say mind-body balance what we really mean is brain-body balance." Lombard and Renna provide a test so readers can determine whether they have a warming or cooling tendency, and then they offer tailored 28-day program that include diet, dietary supplements, exercise, sleep and possible medical treatment. Although the authors say that people can have a dual deficiency, trying to fit into the categories may remind readers of trying to match up with an astrological sign. Interesting points are made, but still it will be hard for many to accept that so much of our mental and physical health is due to a neurotransmitter deficit. Additionally, while many of the authors' recommendations appear sound, they don't provide much evidence for their dietary or supplement advice.