The essays in this volume were presented to Professor Isamu Yamada in honor of his seventy-third birthday. In view of his many professional contributions and associations, a single volume of essays is really insufficient to house the works of all those who wish to be part of a venture of this kind. Therefore, the editors would like to apologize to those friends and well-wishers of Professor Yamada who could not be accommodated in this volume. Born in Nagoya in 1909, Professor Yamada began his brilliant career at Nagoya Commercial College where he studied economics, statistics, mathematics and physics. After serving as a Professor of Economics and Statistics at Yokohama College between 1939-1940, Professor Yamada moved to Hitotsubashi University in Tokyo, where he served as a Professor of Econometrics until his retirement in 1973. Currently, he is teaching at Asia University as a Professor of Economics and Statistics. During his long tenure at Hitotsubashi University (where Professor Ichiro Nakayama, a "Japanese Schumpeter", served as President of the University), Professor Yamada was instrumental in introducing several generation of students to the methods of modern econometrics. One of the editors (Ryuzo Sato) of this volume is a direct beneficiary of his lectures on modern econometric techniques. In the 1950's, Professor Yamada was one of several prominent Japanese economists who were selected for study abroad. It was during this time, on a visit to the Cowles Commission at the University of Chicago, that Professor Yamada met the other editor of this volume.