When mapping cultural and, more specifically, literary history of the Slovaks living in historical Hungarian Lowland, which is - in terms of contemporary political geography - mainly the territory of Slovak enclaves in Serbia, Hungary and Romania, what appears to be one of the important sources is memoirs, written in various periods of time. In the context of the research into the times at the turn of the 20th century, stretching into the following decades of the 20th century, there are several sources of this kind available in books as well as in manuscripts. The subject of the paper is the issues in editorial processing of the memoirs written by Slovak notables who lived and worked in Lowland, especially in the early 20th century, either all their lives (Ján Čajak) or just for a short time (Ivan Thurzo, Pavel Gallo), alternatively by those who, after moving to Slovakia, contributed to the cultural life of that time (Andrej Mráz). The selected writings are similar in subject. However, what is different is the nature of the preserved materials as well as the size, composition, and especially the way they were presented to the readers. While Čajak´s memoirs have not been published to date, those of Thurzo´s and Gall´s were abridged in comparison with the original manuscript versions, and so were those written by Mráz, which were first published in a magazine and later as a book. The focus is given to the textological principles applied to the book edition, editorial changes made in the manuscripts and the issue of the editor´s authority to change the original text.