The book is result of the research project entitled "Key Determinants of Poland's Security in Early 21st Century." The participants of the project are representatives of various academic centres and government institutions. One of the key products of the project is the present publication. The first of its key objectives is to present various aspects of the contemporary security of Poland, such as the military, political, economic, and social aspects, as well as the interdependence between 'hard security' and 'soft security'. The second objective is to demonstrate the correlations between the status of security and the sense of security in Poland. The third objective is to use theoretical deliberations on security in practice, for example based on the pentagonal model of security presented in this publication. Professor Sebastian Wojciechowski and Professor Anna Potyrala had the excellent idea to supplement the scholarly literature in the field of security studies with a unique work - a comprehensive analysis of a specific problem, namely the security of Poland at the start of the new century. This was not an easy task as most researchers focus on the systematic of international (mostly Western) theoretical works and the infrequent publications in this context most often take the form of historical outlines. This makes the publication all the more a success on the part of the Editors and highly qualified Contributors, as they analyzed and diagnosed the relevant subject matter of their research and thus met the objectives presented in the introduction.