Over the last 30 years, the study of ferroelectric oxides has been revolutionized by the implementation of epitaxial-thin-film-based studies that compliment efforts on bulk versions of such materials. This work has driven many advances in the understanding of ferroelectric physics and the realization of novel polar structures and functionalities. New questions have motivated the development of advanced synthesis, characterization, and simulations of epitaxial thin films and, in turn, have provided new insights and applications across the micro-, meso-, and macroscopic length scales. This presentation will trace the evolution of ferroelectric thin-film research from developing understanding of the roles of size and strain on ferroelectrics to using thin-film constraints to create complex hierarchical domain structures, novel polar topologies, and controlled chemical and defect profiles. The extension of epitaxial techniques, coupled with advances in high-throughput simulations, now stands to accelerate the discovery and study of new ferroelectric materials. Coming hand-in-hand with these new materials is new understanding and control of ferroelectric functionalities. Today, researchers are actively working to apply these lessons in a number of
applications, including novel memory and logic architectures, as well as a host of energy conversion devices. This presentation will work to highlight major accomplishments in the field of thin-film ferroelectrics in recent history and, by extension, look towards what comes next for these materials.