Wprowadzenie

In this 39th issue of Zeszyty Naukowe, we present articles on a variety of regional issues. In addition to historical and economic topics, there are also articles devoted to the culture of North-Eastern Mazovia, which include the achievements of Adam Chętnik – the patron of our Society, an outstanding ethnographer, museum curator, social activist and populariser of Kurpie culture. The regional councils of Podlasie and Mazovia have designated 2025 as the Year of Chętka, marking the 140th anniversary of the regionalist's birth. The same resolution was also adopted by the Ostrołęka City Council. The work of this researcher, based on a deep respect for ‘small homelands’, thorough documentation of heritage and concern for the preservation of local traditions, reminds us of the importance of systematic research and popularisation of knowledge about the region. The texts contained in the Notebooks are in line with this trend, showing the richness and diversity of North-Eastern Mazovia.