This book brings together papers presented at an international symposium on centrally acting antihypertensive agents held in Geneva, Switzerland, in association with the 10th Scientific Meeting of the International Society of Hypertension. A major focus of this symposium was the sympatholytic agent, clonidine, and was partly stimulated by the re cent development of an innovative transdermal system for administering this antihyper tensive drug. Although clonidine has been available to clinicians for several years, there has been a re cent reawakening of interest in this type of medication. The centrally-acting antihyper tensive agents appear to be effective both as monotherapy and in combination with other drugs. There are no significant contraindications to their use, and they do not appear to produce metabolic side effects. In this symposium we have paid attention to two types of patients: those with uncomplicated mild hypertension, and those with more difficult forms of hypertension associated with concurrent conditions.