The volume on Vegetable Crops as a part of series entitled "Handbooks of Crop Diversity: Conservation and Use of Genetic Resources" will be a unique resource, first of its kind, which will elaborate on origin, evolution, taxonomy, identification, chemical characterization, genetic improvement of Vegetable Crops Plants. Vegetable crops are an important group of crops comprising solanaceous vegetables, Cole crops, Cucurbitaceous crops, Bulb crops, Root crops, Tuber crops, legume vegetables, leafy vegetables, Okra etc. There is tremendous diversity even within each group. This genetic diversity is from the point of view of landraces and varieties of vegetable crops species used for food, processing, nutraceuticals, pharmaceuticals, etc. Vegetables being an integral part of human diet being rich source of diverse nutrients such as vitamins, minerals and antioxidants, they play an important role in balancing the diet and tackling malnutrition. Besides, due to their intensive cultivation, they also play an important role in enhancing per unit area production and productivity, cropping intensity thereby enhancing the farmers income, especially that of small and marginal farmers, and job opportunities. The genetic improvement of vegetable crops to facilitate continued breeding varieties with greater resilience to stresses and productivity is mainly dependent on overall genetic variation found in individuals belonging to the cultivated species and/or ancestral species related to vegetable cultivated species. Since genes of interest can be tapped from plant sources for their introduction through controlled breeding process for genetic improvement, incorporating desirable external and internal quality traits, therefore accessibility to the information about these plant genetic resources is key to the success of the breeding efforts. There is a need of comprehensive information about the genetic resources, therefore, to facilitate their conservation and long-term sustainable use in research and improvement. The comprehensive information regarding the availability of genetic diversity in each vegetable crop species in this volume would facilitate priority conservation in gene banks, research and use in vegetable crop improvement. Realizing the importance of genetic variability in improvement of crops from the point of view of biotic and abiotic stress resistance, enhanced micronutrient, climate change, enhanced shelf life, nutraceuticals, bioactive compounds especially, national and international efforts further need to be stepped up for collection, characterization, evaluation, and conservation of vegetable plant genetic resources to facilitate search for new genes, research and their use in vegetable crop improvement. During 21st century, genomics and marker assisted tools have gained importance for hastening the crop improvement programmes by enhancing breeding efficiency. Realizing that population in South Asia and Southeast Asia is facing acute problem of under and malnutrition, the emphasis on dietary diversification is being stressed especially with vegetables. Besides, to enhance farmers income much emphasis is being laid on development of varieties having diverse maturity, growth habit, resistance to diseases and insect pest to reduce the use pesticides, enhanced nutrients and shelf life. For these traits, we have to look into landraces, wild relatives for the traits of interest. Therefore, it has been felt to bring out a vegetable volume with additional accessory and supplemental information, analyses and specifically filtered information which can go a long way in promoting research, search for new genes/alleles, revealing the opportunities available for exploitation of PGR in generation of cultivars to meet upcoming challenges of vegetable crop improvement and diversification and requirement of cultivars for processing, nutraceutical and pharmaceutical industry which will promote contract farming. This will also help identification of geographical and genetic diversity gaps for future search of new genes/collections. Based on importance of PGR as treasures of genes of interest for developing improved future vegetable varieties/hybrids and being key to scientific efforts of developing gene pyramided varieties, mitigating various challenges posed by increasing population, climate change and health conscious society, the proposed vegetable volume on agro-biodiversity conservation and use of plant genetic resources with information on available genetic diversity among various groups of vegetable crops and component cultivated species with in a group of food and agriculture in all possible perspectives, would be able to reflect the opportunity available for genetic engineering of vegetable crop species. It will also go a long way in facilitating more predictive and productive genetic engineering programme to breed futuristic vegetable crop varieties/hybrids.