Groundwater is a vital resource for agricultural irrigation, drinking water supply, and ecosystem sustainability, playing a critical role in supporting global food production and environmental health. However, its quality is increasingly threatened by intensive agricultural activities, which are essential for meeting the food demands of a growing population. Agricultural practices such as the application of fertilizers, pesticides, and irrigation water often lead to the contamination of groundwater resources through the leaching of pollutants like nitrates, phosphates, and agrochemicals into aquifers. These contaminants not only degrade water quality but also pose significant risks to human health, ecosystems, and long-term agricultural productivity. Understanding the complex interplay between agriculture and groundwater quality is, therefore, crucial for developing sustainable water management strategies that balance food security with environmental protection. This chapter provides an overview of these critical issues and introduces key concepts such as groundwater contamination pathways, and major agricultural pollutants. By outlining the objectives and scope of the book, this chapter also introduces the main structure of the book, providing readers with the necessary background and context to engage with the detailed discussions in subsequent chapters.