The volume describes about 1250 acyclic sulfur-nitrogen compounds with three- and four-coordinate sulfur in the formal oxidation state IV. Major classes of compounds comprise the species X2S=NR (X=halogen, OR', NR'2, etc.; R=H, halogen, organyl; R'=organyl), (R2N)3S+ (R=alkyl), R2NS(O)X (X=halogen, OH, OR, SR, NR2, R=organyl), (OSNH)x, F2S(NR2)2, and F3SNR2. N,N-Diethylamidotrifluorosulfur, also known under the acronym DAST, has become a very popular fluorinating agent in recent years. Correspondingly, the use of DAST in inorganic and organic chemistry is exemplified with numerous reactions. Some examples are the metathetical exchange reactions converting reactive chlorides into fluorides: SOCl2 -> SOF2, PCl3 -> PF3, (CH3)3SiCl -> (CH3)3SiF, and RC(O)Cl -> RC(O)F. Others include the conversion of (C6H5)3P into (C6H5)3PF2 and of (R3NC(S)S)2 into R2NCF3, R=alkyl. In organic chemistry, fluorides are easily accessible from alcohols, geminal fluorides RR'CF2 from the respective aldehydes or ketones, and acyl fluorides RC(O)F from carboxylic acides by using DAST. Because DAST is easy to handle and gives clean reactions in syntheses, this Gmelin volume devotes much space to the description of the chemical and physical properties od DAST.