Abiotic stress is the negative impact of non-living factors on the living organisms of a specific environment. The non-living variable must influence the environment beyond its normal range of variation to adversely affect the population performance or individual physiology of the organism in a significant way. Abiotic stresses, such as salinity, drought, temperature, and oxidative stress, cause major loss in crop yields. Topics discussed in this book include drought and nutritional stresses in plants; NADP-dependent enzymes and abiotic stress; circadian regulation of abiotic stress tolerance in caenorhabditis elegans; and plant cortical microtubules and abiotic stress signals.