ENTwo closely-related topics are discussed in this monograph. First of all, the author analyses the interaction of two ethnic groups – Lithuanians and Lithuania’s Poles – in the years 1988–1994. Most attention is dedicated to the Lithuanian-Polish ethnic conflict, or more precisely – the goal of Polish activists and organisations to establish national-territorial autonomy. The government of the Lithuanian SSR and later the Republic of Lithuania strictly rejected any efforts made by Poles to establish national-territorial autonomy. In essence, this kind of demand was viewed as a threat to the country’s territorial unity and its national sovereignty. Thus, this study seeks to explain what factors influenced the ethnic conflict between Lithuanians and Lithuania’s Poles, and also analyses the ethnic policy of the Lithuanian government (more specifically, of two political regimes – the LSSR and the Republic of Lithuania). The second topic discussed in this monograph is inter-state relations between Lithuania and Poland. In this study, the author seeks to answer the question of what factors determined the dynamics of relations between the two neighbouring states. Keeping in mind the fact that until March 1990 relations between the Lithuanian SSR and the People’s Republic of Poland were formal, as the nature of their relations was pre-determined and regulated by Moscow, most attention is given to the period following the reinstatement of Lithuania’s statehood. The author tries to explain the circumstances behind the signing of two of the most important inter-state agreements: the Declaration on Friendly Relations and Good-Neighbourly Cooperation (1992) and the Treaty on Friendly Relations and Good-Neighbourly Cooperation (1994).In negotiations on the regulation of inter-state relations, agreement could not be reached on two matters: the guarantee of national minority rights and the so-called assessment of the past. Poland’s negotiators were particularly insistent on the first matter, seeking to include as many regulations that extended minority rights as possible into the agreements, while Lithuanian diplomats focused more on the second matter, demanding recognition in one form or another of Żeligowski’s aggression against Lithuania.