NEARLY 40 YEARS since we declared war on cancer, how goes the campaign against this intractable and ancient adversary? As you will learn in this special edition, our enemy intelligence has improved over the years, enabling us to get a better bead on where the trouble begins. And we have developed stronger weapons, to more precisely pursue and annihilate diseased tissue.

Finding Enemy Forces. Cancer’s origins are multifaceted, a combination of an individual’s genetic factors and influences from the surrounding environment and his or her personal history and lifestyle. Even stem cells—which, in other contexts, offer promise for the treatment of a variety of ailments—could be to blame. To learn more, turn to page 40 for “Stem Cells: The Real Culprits in Cancer?” by Michael F. Clarke and Michael W. Becker. And in “Mapping the Cancer Genome,” on page 22, Francis S. Collins and Anna D. Barker explain how such a tool will help us chart a course across the landscape of human malignancies.

Destroying the Targets. While scientists are grappling to gain a better understanding of cancer’s complex beginnings, they also have improved ways of stalling the advance of the disease. In “Taming Vessels to Treat Cancer,” on page 64, for instance, Rakesh K. Jain describes how calming the chaos in tumors’ blood vessels could facilitate attacking them. Francisco J. Esteva and Gabriel N. Hortobagyi explain how we are also “Gaining Ground on Breast Cancer” with targeted therapies, beginning on page 88.

Hope in the Trenches. Patients with cancer, empowered by expanding informational resources and the changing, more open attitudes of doctors, are living longer and better than ever today, as Lisa Stein writes in “Living with Cancer”; see page 6. Although medicine clearly has much work to do, with advances occurring rapidly, we are on the path to managing this chronic disease.