This book presents a large amount of information related to the heat shock response and heat shock factor (HSF), describes core observations about molecular mechanisms and pathophysiological roles, and provides fundamental concepts on the basis of information from diverse aspects. This adaptive response to high temperature or protein misfolding is a fundamental mechanism to maintain the capacity of protein homeostasis, or proteostasis, and is evolutionally conserved among all living organisms, including bacteria and humans, on the earth. Furthermore, physiological and pathological roles of HSF have been extensively studied in fruit fly, worm, and mouse models. It has been revealed that HSF plays roles in development of the brain, reproductive and sensory organs, and in ageing, inflammation, and circadian rhythm. Analysis of the mechanisms have uncovered that HSF exerts a wide range of effects on gene expression and epigenetic status on the whole genome. Moreover, loss or gain of HSF function is also closely related to protein-misfolding diseases including neurodegenerative diseases, psychiatric diseases, heart diseases, and cancers. Therefore, HSF is now thought to be a promising therapeutic target for treatment of these refractory diseases. For undergraduate students, this is a highly understandable source of information on heart shock response and HSF, covering the basis of HSF biology, the physiological role of HSF, and disease associated with HSF function. This book not only serves as a guide to the heat shock response and HSF for students and young researchers in other fields, but also is a cornerstone for future work in the field related to the heat shock response and HSF.