Layered double hydroxides (LDHs), also known as 2D layered hydroxides, represent a group of explicit anionic clays with customizable chemical configurations with well-defined structural properties. The current chapter comprehensively overviews LDHs, starting with the definition, evolutions in the history, and the basics of structural features, giving importance to the characteristic properties like increased anion-exchange capacity, tunable interlayer spacing, and the flexible characteristics of defined structures. A thorough review of different fabrication processes consists of traditional methods like co-precipitation and hydrothermal synthesis, and advanced techniques like ion exchange, electrochemical decomposition, green synthesis, and template-assisted approaches. This chapter also highlights the strategies for customizing the functionalities via compositional modifications, morphological control, and surface functionalization with active compounds to boost the performance in particular usages. Various usages of LDHs are investigated, ranging from environmental remediation and catalysis to energy storage, drug delivery, and advanced polymer composites. Multi-functionality traits of LDHs in every application demonstrate their capability to address present technological tasks. The chapter concludes with a critical dialogue on present constraints, especially in scaling up the processes, higher stability, and incorporation into multifunctional systems. Review of emerging research focuses consisting with the development of hybrid LDH-based materials and investigations of LDHs in next-generation technologies.