There is a growing realization that many diseases are related to or caused by pathogens. Lack of understanding of evolution of microorganisms makes us ineffective at treating disease.
The evolution of antibiotic resistance is a good case in point. Working with advanced electromagnetic technologies to eliminate pathogens quickly demonstrates that evolution of microorganisms can occur quickly enough to affect treatment during the course of treating a single episode of a disease in a single patient. There needs to be a new field of the science of internal ecology of the body that builds understanding of the ecosystems of the microbiological agents that outnumber our cells.
That said, Nesse and Williams give an easily readable primer on some of the fundamental evolutionary thinking essential for successful understanding and treatment of disease. It is unfortunate that more physicians are not deeply familiar with these issues. The improper handling of disease with current antibiotics makes the organisms that cause them more deadly. This could easily be minimized by correctly approaching treatment from a base of understanding of evolutionary biology.
While this book is a good step into the deep waters of internal ecology, its easy reading makes it somewhat superficial. To start getting the real scoop, you need to read Ewald's work. A good starting point is Plague Time: How Stealth Infections Cause Cancer, Heart Disease, and Other Deadly Ailments.
As one simple example, Plague Time points out that the Borna virus is usually associated with Bipolar disease. After working with a few individuals with Bipolar disease, I've found they invariably have the Borna virus. This is untreatable by conventional medicine. Using electromagnetic techniques, the virus can be eliminated or reduced in number. This results in immediate cessation of a manic/depressive episode in some people. There are numerous other examples of these issues in heart disease, cancer, auto-immune diseases, and so forth.
The fact that microorganisms are becoming more resistant to treatment and getting deadlier from improper management, combined with the fact that many diseases are caused by unrecognized pathogens, means that every individual needs to come to grips with evolutionary biology or risk becoming a victim of it.