More than three years have passed since the death of Alexander Stepanovich Karpenko, our colleague and friend, on February 7, 2017. He combined high professionalism in the ﬁeld of logic with an infectious love of life, which attracted many logicians both in our country and abroad. Since 1993, volumes of the yearbook “Logical Investigations” began to come out. In 2015, thanks to the organizational eﬀorts of A. Karpenko, the yearbook became a journal which now comes out twice a year. Russian and foreign authors publish their works in it, which allows us to maintain our logical life and communication. We decided to devote the present issue to the memory of A. Karpenko by inviting famous logicians who not only knew him, but who could be called his friends, to publish their works. Unsurprisingly, our call received a lively response. We bring to your attention works on current topics of the science so beloved by us and A. Karpenko.
The issue also contains a full List of publications of A. Karpenko.