The big question: what is the most pressing health crisis and how can it be solved?

It is perhaps the single most elusive question today-how to manage and care for the billions of people who will fall ill this year, often terminally, in nations rich and poor? In so many cases the status of health is a purely financial question. Far too often poor health is simply a question of ignorance or the absence of drugs, medical facilities, clean water and a healthy environment. To help inform the debate, World Policy Journal asked a panel of experts to weigh in on what they see as the most pressing health crisis today and how it can be solved.