The Journal of Applied Non-Classical Logics is the continuation of a bulletin set up in the 80s of the last century by Luis Fariñas del Cerro and Ewa Orłowska. In the days of its foundation, the field of science covered by our journal was still in its infancy. With the advent of epistemic logic and temporal logic, the parts of artificial intelligence and computer science concerned by knowledge representation and program verification were seething with excitement. With the coming out of formalisms such as description logic and dynamic logic, the development of non-classical logics was not long in going at full speed. The "raison d’être" of a scientific journal is to promote the progress of a field of science by reporting new research. Over the last twenty years, through regular or special issues, our journal has covered all aspects — theoretical and practical — of research in the field of applied non-classical logics. And most of the prominent researchers in deontic logic, description logic, dynamic logic, epistemic logic, intuitionistic logic, many-valued logic, modal logic, non-monotonic logic, paraconsistent logic, spatial logic, temporal logic and uncertainty logic have already presented in its columns some of their most important contributions. Celebrating today the 20th anniversary of the foundation of our journal, this issue and the previous one present twelve articles carried out by renowned researchers. We would like to thank them all for their enthusiasm and their support. The task of continuously representing the latest developments is never easy. Over and above the editorial work of the journal administrators, it requires the benevolent contributions of anonymous referees. On the occasion of this 20th anniversary, let us thank them all for the willingness and the competence they put in ensuring that accepted articles meet the highest standards of quality and validity.