This book summarises more than a decade of work conducted by two researchers who set out to verify in archival sources the existing biographical information about Fryderyk Chopin, his family and his friends, and also to obtain new material to expand our knowledge of his ancestors. The research covered approximately 100,000 handwritten legal documents from Kuyavia, Mazovia and Royal Prussia, numerous printed and cartographic sources, and also the subject literature. The majority of sources held in Polish archives were examined, as well as information from France and Russia.