The design of environment-sensitive devices for biomedical and pharmaceutical applications has improved significantly due to recent advances in smart polymer and hydrogel technology. Despite their capacity to carry out functions that previously were unobtainable, smart polymers and hydrogels tend to have painfully slow response times. On the other hand biological systems go through phase changes at an extremely fast rate. This book examines the natural systems that respond almost instantaneously to environmental stimuli, and thus gives the reader an understanding of the mechanisms that govern these responses. The book includes chapters on how to go about designing a synthetic ìflashî system based on the naturally occurring systems. It also deals with potential applications of flash systems in biomedical and pharmaceutical areas.