This book provides essential information on improving protein folding/stability, which is a result of the balance between the intra-molecular interactions of protein functional groups and their interactions with the solvent environment. The protein folding solvent environment mainly consists of salts, small molecule compounds, metabolites, molecular chaperones and other chemical species. Therefore, subtle change in the composition of the environment will alter the protein folding process. The importance of the solvent environment in protein folding is precisely due to the fact that various disease-causing proteopathies can be reversed by manipulating the solvent environment of the malfolded proteins. Hostile environmental stresses represent one of the basic causes of such challenges in protein folding or misfolding. Since cells commonly encounter extreme environmental fluctuations, it is crucial that they equip themselves with strategies to circumvent the hostile environmental conditions. Nature has developed many strategies to ensure that the complex and challenging protein folding reaction occurs with adequate efficiency and fidelity for the success of the organism. Among the strategies employed in a wide range of species and cell types is the elaboration of small organic molecules called osmolytes. Additionally, recent advances have also revealed that certain specific osmolytes might be key biomarkers of cancer, infectious diseases and vaccine flocculation. In fact, a large pool of data has been generated regarding their potential for the therapeutic intervention of neurodegenerative diseases and other metabolic disorders caused by protein aggregation or proteostasis failure. Reflecting the multiple applications of these small molecules in the health and other industries, this book combines contributions by respected leaders in the field and will help to inspire college students, basic researchers, and clinicians to translate these biological roles of osmolytes into clinical practice. It will also shed light on some important future prospects of osmolytes like their role as drug excipients and provide a deeper understanding of their mechanism of action in the prevention of neuro-degenerative diseases.