The importance of sustainable development in its truest sense is to recognize the significant contribution of natural resources toward the welfare of the human being and the betterment of human civilization. Natural environment has never been considered in development literature as an important part of the production process due to the lack of clearly defined property rights. It gave birth to a completely new branch, namely Ecological Economics. Based on the structure and openness, ecosystems have features such as ecosystem is a well-designed structural and serviceable unit of ecology and is defined by species diversity. Further, the energy budget controls the operation of an ecosystem and the ecosystem controls both material cycles and energy flow. In the process, further complex ecosystems are formed. Natural ecosystems are divided into terrestrial ecosystem and aquatic ecosystem. In addition, there can be artificial ecosystems, which are shaped and maintained by the human being with certain pre-determined objectives. Gradually the importance of ecosystem services started to attract social scientists and development practitioners due to its contributions that generate goods, valuable to people and, largely, society. To capture the benefits provided by nature to society, an identification of ecosystem goods and services is of immense importance. Provisioning, regulating, socio-cultural, and supporting services were mentioned, followed by the ecosystem services paradigm, started from Millennium Ecosystem Assessment (MA) in 2003 to Common International Classification of Ecosystem Services (CICSE) in 2013, through The Economics of Ecosystem and Biodiversity (TEEB) in 2010. In the fifth section, emphasis has been given to economic valuation of ecosystem services, where monetary valuation method and a brief idea of total economic value method have been discussed in detail. Section 18.5.1 elaborates three important techniques used in the valuation of ecosystem services, namely direct market valuation approach, revealed preference approach, and stated preference approach. The difference between revealed preference and stated preference has also been reflected in this section. It is the fact that after the introduction of the concept of sustainable development, the incorporation of non-marketed services, especially ecosystem services, has gained worldwide importance.