Memorial of Ing. Jiří Čejka, DrSc. (1929-2025)

Ji ejka's truly remarkable, extraordinary, and fruitful life came to an end on September 2, 2025, the day of his 96 th birthday, in his birthplace and lifelong hometown of Roudnice nad Labem (Czech Republic).To many, he was also known by his Scout nickname Pguy, after his beloved French poet.To us, he was simply Jirka (Fig. 1).As a true testament to his indomitable spirit and work ethic, Jirka remained scientifically active until last year.In fact, some of the papers he has co-authored have not yet been published, but they will be in his memory.Jirka was a prominent researcher, particularly in spectroscopy and thermal analysis of uranium minerals and compounds.In tribute to his lasting influence, we have prepared this memorial issue promptly, with contributions from colleagues who worked closely with him in recent years or whose research was shaped by his influence.Before presenting those reflections, though, we would like to offer a brief remembrance of his life and work.As an appendix