Optical wireless communications (OWCs) employing electromagnetic waves in optical wavebands as information carriers can achieve higher communication bandwidth compared with radio frequency based wireless communication. However, the good directionality of optical waves degrades its non-line-of-sightNon-line-of-sight (NLOS) transmission ability for avoiding obstacles. Ultraviolet (UV) communications working in “solar blind” wavebands (200–280 nm) can well overcome this drawback of OWCs and achieve NLOS links due to the strong scattering effectScattering effect of the ultraviolet lights passing through the atmosphere. In this chapter, we first present the basic idea and potential applications of UV communication in Sect. 1.1. Then we introduce the research history of UV communication in Sect. 1.2. Then we introduce the key technologies evolved in UV communications in Sect. 1.3. In Sect. 1.4, we summarize this chapter and introduce the structure of this book.