The book presents a comprehensive, yet concise analysis of groundwater occurrence, its development, technology involved in exploration, extraction, and its economical usage.The book makes use of minimum technical jargon, while explaining the basics of drilling, types of wells, their maintenance, development and testing, and selection of pumps. It discusses the causes for wells failing, methods of diagnosis and the pre-emptive and remedial measures, water transmission, composition, and purification. Unlike other natural resources, groundwater is replenished by rainfall. Nevertheless those who depend on groundwater either for industrial or agricultural sustenance should be responsive to certain factors that are significant to the long-term well-being of the water source. Important are: Whether the wells are being over-pumped, or under-pumped; the quantity and cost of water being drawn, whether there is sufficient water underground with optimum replenishment, and systems installed are compatible to the particular hydrological situation and similar such factors. The book attempts, in simplistic language, to link the gap between theory and practice; between the principles of groundwater as a natural science and its application technology. There are a number of pre-calculated tables that serve as a handy reference for Consultants, Drillers and Engineers who deal with groundwater on a day-to-day basis.