The contributions focus on succession and obligation law norms shaping the legal status of an heir and their comparison within Polish and German law systems. They analyse the impact of the instruments of contract law on the status of an heir. The adopted methodology combining the internal-national and external-comparative perspective allows the authors to present “similarities in dissimilarities” within institutions of the German and Polish succession law. The broad analyses of legal doctrine and jurisprudence can serve as a source of knowledge and points of reference for legal practitioners, courts and legislators.