This is the revised and enlarged version of the author's Ph.D. Dissertation which was first published in 1973. The present edition has been prompted by the wide acceptability and encouraging reception the first edition received internationally among the students and academic community engaged in the study of Nepal. The first edition was extensively reviewed in media and academic journals of international repute, and introduced as a text/reference book at the level of graduate level studies in Political Science and International Relations in many colleges and universities.The revised edition presents an objective and critical assessment of the historical roots, objectives & determinants, and the evolution of Nepal's foreign policy for the past nearly seventy years (1951-2016). A close nexus that exists between Nepal's domestic politics and its foreign policy has been sharply brought out in this book. It includes relevant documents and data sheets to throw light on the significant landmarks in Nepal's conduct of its external affairs.