University of Szeged, Bolyai Institute, Szeged, Aradi vértanúk tere 1, Hungary 6720.
It is a great honor for me to write a few introductory words to the present volume of CGASA dedicated to Professor George A. Grätzer. The occasion for this dedication is that we are celebrating two anniversaries in 2018 related to him. Namely,
(A1) it was 55 years ago that the Grätzer--Schmidt Theorem was published, and
(A2) it was 40 years ago that G. Grätzer's General Lattice Theory, which immediately became the Book in lattice theory for decades, appeared.