Abstract. We survey eleven papers by György Pollák published from 1973 to 1989 and devoted to various aspects of the theory of semigroup varieties: hereditarily finitely based varieties, permutation identities, covers in varietal lattices.

AMS Subject Classification (1991): 20M07, 08B05, 08B15

Received February 18, 2002. (Registered under 2873/2009.)