The book is a collection of 11 research papers of the author’s himself. These papers which contain econometric analysis of theory and policy in Economics, have been written during 2019 and 2020 and have been published in different national and international journals. The studies cover mainly on China-USA trade patterns, the cycles and seasonal patterns of NEER and REER of Chinese RMB, determinants of NEER and REER of Chinese RMB, empirical verification of quantity theory in the UK, nature of unemployment cycles of USA, ASEAN’s trade and the single currency, Indo-UK trade during the gold standard, determinants of India’s health expenditure, India’s trade flows and GDP in the gold standard, Bretton Woods and post Bretton Woods regimes, decoupling India’s CO2 emission and the determinants of the manufacturing industry in NE Regions respectively. Modern econometric models have been applied to analyse the above economic relationships. The book is useful to the econometricians, teachers and students who generally apply econometric tools in economics. The book will satisfy the policymakers to some extents. Contents include : The Dimensions and Patterns of Sino-US Trade; Patterns of Trends and Cycles of Nominal Effective Exchange Rate and Real Effective Exchange Rate of Chinese Renminbi; Determinants of Nominal Effective Exchange Rate (NEER) and Real Effective Exchange Rate (REER) of Chinese Renminbi (RMB); Empirical Evidence of Quantity Theory of Money in U.K.; Cyclical and Seasonal Patterns of US Unemployment Level during 1948-2020; Empirical Study on the Prospects of ASEAN’s Trade and a Single Currency; Indo-Britain Trade during Gold Standard : An Econometric View; India’s GDP and Trade Flows during Gold Standard, Bretton Woods and Post-Bretton Woods Periods : A Comparative Empirical Study; Determinants of India’s Health Expenditure : An Econometric Analysis; Decoupling CO2 Emission Per Capita in India with GDP Per Capita and Other Determinants; Econometric Analysis of Manufacturing Industry and its Determinants in the North East Region in India.