A thought that often crosses the minds of people searching for an explanation for their ailments. They suffer from increased susceptibility to infections, intolerances, allergies, and also autoimmune diseases. Hashimoto's and fibromyalgia are just two examples from a whole range of conditions characterized by a disturbance of the immune system. But what is the immune system and how does it work? The science of psychoneuroimmunology is based on the relatively new understanding that the hormonal system, immune system, and psyche form a network that functions like a sensory organ. This leads to the important realization for both practitioners and patients that all three areas must be addressed in the corresponding conditions to achieve a satisfactory outcome, namely, the well-being of the patients.