Increasing water scarcity is a global issue, posing great threat to the animal and plant life. Identification of drought tolerant genes, investigation of networks of gene interaction and their regulation can pave a way to the development of crops which can grow and survive in water shortages. In this volume, methods have been described to identify drought tolerant genes in cotton by single gene and high throughput approach. Moreover the ways to characterize the identified genes are exemplary. A new way of using microarrays to identify similarities and differences among various genomes and use of these comparisons for identification of novel genes involved in important phenomenon is the heart of this book.