Book excerpt: This book presents theory, fundamentals and applications of ferroelectricy. 24 chapters gather reviews and research reports covering the spectrum of ferroelectricity. It describes the current levels of understanding of various aspects of ferroelectricity as presented by authorities in the field. Topics include relaxors, piezoelectrics, microscale and nanoscale studies, polymers and composites, unusual properties, and techniques and devices. The book is intended for physicists, engineers and materials scientists working with ferroelectric materials.