After a brief recall of layered double hydroxides (LDH) features to underline the reasons of the present exponential growth of the number of patents and papers dealing with application in several sometime unexpected fields, the chapter will deal only with selected applications, namely, (1) environmental protection and agricultural aids; (2) heterogeneous catalysis; (3) nanofillers for polymers; (4) photophysics and photochemistry; (5) biotechnology; and (6) pharmaceutical technology and cosmetics. Also are described the preparation of LDH nanocrystals and their exfoliation into individual layers to be used as building blocks for the layer-by-layer deposition of functional thin films containing luminescent dyes, molecular magnets, quantum dots for potential application in several electronic devices. At the end of this chapter, a brief note describes other potential niche applications and future developments.
