The Fourth Migraine Symposiumheldon September 11th, 1970 was deliberately slanted towards a different audience from the earlier meetings. An attempt was made to interest General Practitioners rather than Scientists in some of the problems associated with diagnosis and therapy in migraine. Y et the volume does include two papers of a more scientific nature and these may be of some interest to those physiologists and biochemists interested in this common disorder. References are those given by each author, but as far as possible they have been checked and are presented here in as uniform a manner as possible. Dr Raymond Greene most kindly acted throughout the entirc meeting as a most excellent Chairman. Our thanks are also due and are given to The Migraine Trust for their part in the organizing of the meeting, to Miss S. Barkwell, my secretary, for her painstaking assist­ ance, and to the Department of Medical Illustration for preparing the figures in Chapters I, 3, 4 and I 0. November, I970 J. N. CUMINGS Editor viii Chairman: DR RA YMOND GREENE OPENING ADDRESS Sir John Richardson As a generat physician, I am naturally very greatly honoured at being invited tobe the first speaker at this Fourth Symposium of the Migraine Trust. Migraine certainly deserves special study because of the enormous morbidity that it causes throughout the world. I understand that it has been estimated that there are seven million sufferers in this country alone.