Fiorella Castelli passed away, much too early, on 2019 July 26, at the age of 76. Her work together with R. L. Kurucz on ATLAS9 model atmospheres is well-known and widely used by astronomers all over the world. Fiorella’s synthetic spectral libraries for multiwavelength observations, from the UV to the near-infrared, for different types of stars are also famous and indispensable in studies of chemical abundances. We are loosing not only an excellent highly valued scientist, but also a wonderful person always greatly helping colleagues in their work. Our thoughts are with her family.