Essential hypertension is a heterogeneous group of disorders of no definable cause. The commonly accepted view is that genetic influences interact with environmental factors in the onset of this chronic and degenerative disease. The aim of researchers in this field is to unravel the molecular and genetic architectures of the disease. The methods of molecular genetics are greatly contributing to decipher the puzzle and much information has been gathered lately. The powerful combination of linkage, sibpair and association analyses, together with studies of human genetic isolates and animal models allow the identification of specific genetic influences and the development of attempts at gene therapy. The aim of this mongraph is to provide coverage of some of these different aspects of modern research in hypertension and a summary of what amounts to an enormous body of literature.