The article reviews the use of environmental DNA (eDNA) metabarcoding for surveying animal and plant richness, highlighting its advantages over conventional methods. eDNA metabarcoding leverages high-throughput sequencing (HTS) to rapidly sequence DNA from environmental samples, enabling noninvasive surveys of species richness in various ecosystems. The authors discuss the challenges in estimating relative abundance using eDNA and provide guidelines for study design, focusing on primer selection and library preparation. They also explore the spatial and temporal scales of inference for different eDNA sample types, such as surface water, groundwater, and sediment cores. The article emphasizes the importance of understanding the ecology of eDNA, including its origin, transport, and fate, to improve the accuracy of abundance estimates. Additionally, it addresses the need for further research on the spatiotemporal dynamics of eDNA and the development of robust bioinformatics pipelines for data processing. Finally, the authors discuss emerging applications of eDNA metabarcoding in ecology, conservation, and citizen science.The article reviews the use of environmental DNA (eDNA) metabarcoding for surveying animal and plant richness, highlighting its advantages over conventional methods. eDNA metabarcoding leverages high-throughput sequencing (HTS) to rapidly sequence DNA from environmental samples, enabling noninvasive surveys of species richness in various ecosystems. The authors discuss the challenges in estimating relative abundance using eDNA and provide guidelines for study design, focusing on primer selection and library preparation. They also explore the spatial and temporal scales of inference for different eDNA sample types, such as surface water, groundwater, and sediment cores. The article emphasizes the importance of understanding the ecology of eDNA, including its origin, transport, and fate, to improve the accuracy of abundance estimates. Additionally, it addresses the need for further research on the spatiotemporal dynamics of eDNA and the development of robust bioinformatics pipelines for data processing. Finally, the authors discuss emerging applications of eDNA metabarcoding in ecology, conservation, and citizen science.