Lech T. Polkowski graduated as MSc Eng. from Chemical Department of Warsaw

University of Technology in 1969 and after a stay at the Polish Academy of Sciences as a doctoral student in Physical Chemistry, he graduated from Department of Mathematics, Mechanics and Computer Science of the Warsaw University as MSc in Theoretical Mathematics. A result from his Master Thesis is quoted in monographs on set-theoretic topology. He obtained a PhD in Mathematics in February 1982 with a thesis on infinite dimension theory and a result is quoted in monographs on Dimension Theory.

He lectured in years 1985-87 and 1990-91 at Math Department of Ohio University, Athens Ohio, US, and was a guest scholar at Vakgroep Informatika at Delftse Universiteit, the Netherlands, in 1988-89.

His works at that time were devoted to topology, published in Fundamenta Mathematicae, Proc. Amer. Math. Soc., Topology Proc., and to aspects of language: Montague Grammars, models of anaphoric resolution, in few booklets available at Koninklijke Bibliotheek, the Hague.

In 1992, in Poland, on advice of professor Helena Rasiowa, he started working on rough sets, with Zdzisław Pawlak. With Andrzej Skowron he wrote a number of papers on morphology of rough sets, fusion of information, also on approximating grammars, with Gheorghe Paun from Romanian Academy.

He created the theory of rough mereology which in a sense `fuzzifies' classical extensional mereology proposed and formalized by Stanisław Leśniewski.

His individual contributions encompass also a formal theory of granulation of knowledge and a resulting approach to granular classifiers as well as work on spatial reasoning with applications to navigation and control of intelligent agents (e.g., mobile autonomous robots).

He collected results of research on rough mereology in monographs: Approximate Reasoning by Parts and Granular Computing in Decision Approximation (the latter with P. Artiemjew) both by Springer.

He is a Professor ordinary at Polish-Japanese Institute of IT, in Warsaw, and at the University of Warmia and Mazury, in Olsztyn, Poland. He served as a member of Program Committees or Advisory Boards of about 60 plus international conferences, including the first RSCTC'98 conference in Warsaw which he co-organized. He served on Editorial Boards of Grammars (Kluwer, nonexisting now), Fundamenta Informaticae as Deputy Editor’s-in-Chief, now he serves on EB’s of Paladyn. Int. J. Behavioral Robotics, JAMRIS (J. Automation, Mobile Robotics, Intelligent Systems), Trans. Rough Sets.

He authored over 240 papers with over 6000 citations (according to Google Scholar). He is glad that his book on Rough Sets. Mathematical Foundations by Springer helps people in rough sets for over 14 years having over 600 citations and that his tutorial on rough sets with A. Skowron and J. Komorowski has been quoted 1000 times.