Increasing agricultural productivity to meet the demands of growing population is a challenging task. Abiotic stresses are among the major limiting factors on agriculture. The knowledge and research programmes on the physiology and molecular biology of stress tolerance are certainly helpful to counter act this negative effect to a great extent. The present literature deals in detail mostly with plant responses to different abiotic stresses. There have been extensive studies, in the past few decades, on the physiology and biochemistry of plant responses to abiotic stress conditions, in the laboratory as well as in the field. However, the interest has shifted to molecular biology of stress tolerance, modes of installing tolerance mechanisms in crop plants. Microarray technology, functional genomics, development of high throughput proteomics would benefit and guide the physiologists, molecular biologists and biotechnologists to enhance stress tolerance in plants. We therefore, felt very strongly that there is an immediate and urgent need for a textbook on this important topic. This book would be an ideal source of scientific information to the postgraduate students, research workers, faculty and scientists involved in agriculture, plant sciences, molecular biology, biochemistry, biotechnology and related areas. We would like to thank the authors for their interest and cooperation in this exciting venture. We are grateful to Jacco Flipsen and Noeline Gibson of Springer for their continuous support and technical advice in bringing out the book. K. V. Madhava Rao A. S. Raghavendra September 2005. K.