Significant progress has been made in understanding the factors that are driving the stabilization of the metastable ferroelectric phase and the degradation mechanisms during field cycling and storage as well as demonstrating a large number of different devices. This special topic brings together a collection of articles dealing with all aspects of ferroelectric hafnium oxide from the material and device viewpoint. The current status of the research in the emerging fluorite-structured ferroelectrics is reviewed with introducing related letters included in this special topic. One of the topics is the mechanism of the ferroelectric phase formation. This special topic includes important contributions for the continuous improvement in ferroelectricity in fluorite-structured oxides.