Disease and illness have always challenged human existence, and healthcare has mirrored humanity's social evolution and acquisition of scientific knowledge. As cities grew, populations multiplied, and long-distance travel increased, larger outbreaks of infectious diseases became possible. As our activity level, diet, and longevity have changed, we have increasingly had to treat diseases of the joints, cardiovascular diseases, and cancers. Similarly, our understanding of what causes these and other diseases has evolved from attributing their origin to demonic forces and the imbalance of elements such as the four bodily humors to today's scientific understandings of microbiology, cell biology, and genetics. With our increased knowledge came vastly improved treatments. The days of bleeding patients to treat fevers are gone. We have vaccines to prevent infections. But as society and science have advanced, we continue to be challenged by new diseases and providing access to healthcare for all people. These are two of today's greatest healthcare challenges, and this chapter, like the others in this book, focuses on various aspects of how we can be more successful in addressing them.

To overcome the unmet health needs throughout the world, we need new approaches based upon sound principles. We are in an era of tremendous innovation with great potential for increasing access to quality healthcare around the globe. With nearly 60 percent of the growth in worldwide GDP through 2020 expected to occur in emerging markets such as China, Brazil, India, Mexico, and Russia, new collaborative approaches and new ways of working in global partnerships across geographies and companies will be required if we are to successfully address our healthcare challenges.