This critical, compact book presents and evaluates the methods available for the measurement of pituitary and chorionic gonadotrophins, thyrotrophin, adrenocorticotrophin, growth hormone, prolactin, antidiuretic hormone and antidiuretic substances, estrogens, progesterone and its metabolites, corticosteroids, 17-ketosteroids and androgens, adrenaline and noradrenaline, and insulin. The clinician interested in endocrinology will find this book to be of special value because of its emphasis on the selection of the most suitable methods for clinical studies. Reasons for selecting a particular method and the scope and limitations of the various methods are well presented. Applications to clinical problems of the results of hormone assay and future fields of investigation are discussed. The author achieves the difficult goal of setting the methodology of hormone assay in perspective. A healthy scepticism is evident in presentation of errors and pitfalls of the past. The achievements of the Edinburgh group are emphasized.