This open access book introduces the science of the new materials soft crystals by showing
various interesting examples. Different from conventional hard and stable crystals the soft
crystals respond to gentle stimuli such as vapor exposure and rubbing but maintain their
structural order. In this book their exhibition of remarkable visual changes in their shape
color and luminescence is described. Through the chapters historical background recent
remarkable developments and future prospects are described concisely. This book helps readers
to understand a new concept of materials that have the characteristics of stimulus-sensitive
soft matter and finely controlled crystals and to design novel materials with the
characteristics. The English translation of this book from its Japanese language original
manuscript was done with the help of artificial intelligence (machine translation by the
service DeepL.com). The text has subsequently been revised further by a professional copy
editor in order to refine the work stylistically.
