The book contains seven analytical reviews of leading scientists in Europe and the USA. The material provides insight into important changes that have occurred in ferroelectric physics over the past 20 years. Conceptual achievements of the theory of ferroelectricity, new technologies for obtaining thin epitaxial films of oxide ferroelectrics and superlattices and methods for their research are considered. The results of theoretical and experimental studies of dimensional effects in thin and ultrafine ferroelectric films, ferroelectric nanoparticles and nanotubes are described.