The history of Acta Theriologica is inextricably linked with that of its eminent founder, Professor August Dehnel (1903– 1962), and the Mammal Research Institute of the Polish Academy of Sciences in Bialowieza. The first issue of the journal was published in January 1955, by the Institute of Zoology of the Polish Academy of Sciences. In the same year, the Mammal Research Institute became an independent entity within the Department of Biological Sciences, Polish Academy of Sciences, and in 1958, it took over the publication of Acta. From the outset, Acta Theriologica aimed to be an international journal, with articles published in one of four languages: English, German, French and Russian. Since the 1970s, almost every article has been published in English. During the 60 years of its existence, Acta Theriologica has communicated over 2500 articles, including original papers, short notes and book reviews, submitted by researchers from six continents. A total of 59 regular volumes have been published since 1955, including seven special issues. Now, in 2015, we proudly present the sixtieth volume, which underlines the long and successful history of our journal.