Duo Qin has provided a scholarly study of a crucial period in the history of econometrics. She traces the formation of econometric theory during the period 1930-1960, and focuses on the formalization of mathematical and scientific processes to analyse economic problems. This book deals with the advances made in the practice of econometrics as a discipline, in terms of the basic issues in econometric modelling: the probability of foundations, estimations, identification, testing, and model construction and specification.