A. Szalay - centenary celebration day at the ATOMKI Institute, Debrecen (Zs. Fülöp) D. Berényi: Alexander Szalay A. S. Szalay: Events, observations and the forming of my individuality in a scientist's family I. Hamvas: The Hungarian uranium É. Svingor: Do we provide or do we serve? Á. Z. Kiss: Accelerated ion beam research at ATOMKI K. Balogh, Z. Pécskay: The K-Ar Laboratory of ATOMKIand its activities L. Galuska: Professor Szalay's influence on the nuclear medicine in Debrecen Á. Molnár: Alexander Szalay, a pioneer of sonochemistry Z. Győri: Alexander Szalay's observations on the soil-plant system EVENTS