Migraine treatment improved considerably with the advent of the 'triptans' in the 1990s. While the drugs used previously for headache treatment had efficacy, some compounds had bothersome side effects and their overuse could lead to severe complications. In the early days of the triptans, itwas widely presumed that migraine was no longer a treatment problem. However, it has gradually been recognized that a significant proportion of patients are not responsive to triptans or do not tolerate them. It is now clear that, even with effective treatment, patients with frequent migraineattacks are not treated well exclusively with acute medications. This is partly because patients are still bothered by the attacks and partly because frequent intake of acute medication may result in medication-overuse headache. These problems have led to a renewed interest in preventive migrainedrugs. Part of the Frontiers in Headache Research series, this book summarizes the several promising new avenues for the development of future drugs for the treatment of migraine, including cortical-spreading depression inhibition, nitric oxide synthase inhibition and calcitonin gene-related peptide (CGRP)receptor antagonism, as well as other potential targets. The book presents frontline knowledge of these evolving modalities as far as it is available in the public domain. It is hoped that readers and their patients will find it exciting to learn about all the novel possibilities, and also that theimpressive research advances in migraine will lead to increased funding, not only of migraine but also of other types of headache.