In his seminal 1971 New England Journal of Medicine paper M. Judah Folkman wrote, “The mechanism by which tumour implants stimulate neovascularization must be well understood before therapy based on interference with angiogenesis can be devised.” Although research on angiogenesis was well-founded by this time, its potential therapeutic value for treating patients with cancer had not been voiced. Folkman's research changed this.

In the Timeline on p647 of this month's Focus issue on Targeting Angiogenesis, Bruce Zetter documents the contributions that Folkman made. These were numerous and occasionally not well-received, but always served to stimulate important debate about how a developing tumour can alter the balance of pro- and anti-angiogenic factors such that angiogenesis is the prevailing outcome. Research on tumour angiogenesis has come a long way since 1971, as Zetter notes: “what started as an idea from a young surgeon grew into a hypothesis, then into a field and now into an industry where it is rare to find a pharmaceutical company without an angiogenesis programme. Few ideas generate so much traction.” This is one reason why it made sense to commission an article on Folkman's achievements to go with our Focus issue on Targeting Angiogenesis. Reading through the accomplishments of Folkman and the many scientists who worked with him during his career not only puts into perspective what research on angiogenesis has achieved, but also what goals still need to be realized so that the current response of a few patients to anti-angiogenic therapies can be achieved in many.

All of the relevant content from this Focus issue, as well as other Reviews, Perspectives and articles on tumour angiogenesis from the Nature Publishing Group are online at http://www.nature.com/nrc/focus/targeting_ang and we thank Pfizer for supporting this Focus issue.