Plants have vital role in the lives of Humans, especially Cereal crops are important source of food for Human and other animals. Some environmental factor limiting the yield of these commercially important plants, heat stress is one of these factors. Now there is need to produce the more yield of the plants under limiting environmental conditions to fulfill the requirements of humans and other animals by producing the research techniques. The present book describes the environmental heat stress impacts on the plants especially on maize. Heat stress effects the morphology, physiology and reducing the yield of the maize crop. Plants adapt different methods to cope with the heat stress condition, heat stress produce reactive oxygen species that retards the plants growth. Heat shock protein development has been found in tolerant plants. Different osmoprotectants are used as priming and foliar treatments to improve the crop’s growth and yield.