Environmental stresses, such as high and low temperature, salinity, and drought, represent limiting factors to agricultural productivity worldwide. Their impact is not only on crops that are presently being cultivated, but they are also significant barriers to the introduction of crop plants into noncultivated areas. The book describes the cellular, biochemical, and molecular mechanisms in plants that regulate tolerance to stresses. Also discussed are prospects of engineering stress-tolerant plants through the modification of germplasm.