I began my research for a special reason – to find the members of my family – past and present – who are carriers of a rare mutation of the Beta Thalassemia genetic trait. I have traced them back to the area around Ostrów Mazowiecka, and the vital records and Books of Residents of that town have been the core of my genetic-related research. And, Ostrów Mazowiecka is not an exceptional case; these registers have survived for many other towns and they are available in branches of the Polish State Archives or, in the case of records less then 100 years old, in the towns’ civil records offices.
