Human beings are much more complex than any technology we could devise today. How many machines are good for 80 or 90 years of service? Our immune system—set up at birth—is able to repel diseases that don’t even exist yet. Most viruses that proliferate 50 years after we were born can be defeated just as easily as maladies that have been dogging humans for generations. Effective health care means that—in most regions of the planet—we are living longer and longer. All the same, human beings are not perfect: We get sick and we wear out over time. In the wealthier regions, we spend a great deal of money trying to get as close as possible to a 100-year span. Our greatest task is to bring a long and healthy life within the reach of as many people as possible. New technology is required to hold down the cost of health care, to nip outbreaks of disease in the bud, and to ease discomfort in our old age. Scientists believe that substantial benefits can be gained by identifying abnormalities earlier. A cancerous growth measuring just a few millimeters is still relatively harmless, and an infection caught in its early stages won’t leave any scars. Although techniques for accurately diagnosing incipient abnormalities can often be very expensive, prompt diagnosis generally means that treatment will be easier, cheaper, and more likely to succeed. Thus, we can end up saving money despite the need for expensive equipment. To adequately fight the outbreak of diseases in the future, our technology must be able to respond more rapidly. This could pose a particular challenge because there is also a trend at present toward superspecialization, which is fragmenting medical knowledge and slowing down responses. Take the science of ophthalmology in which the various specializations focus on extremely specific parts of the eye. This is fine once a precise diagnosis has been made, but it could be a significant problem if the patient consults the wrong doctor at the outset. The way we currently approach diagnosis needs to change.