This chapter covers the period 1995–2003, but also contains relevant material from the period 1953–1994 not fully covered in COFGT (1995). Apart from its mainstay, the tetrahalomethanes, this chapter treats trihalomethyl derivatives of almost all elements. Especially biologically active trifluoromethyl ethers, sulfides, sulfoxides, and sulfones have been prepared in large numbers during the development of contemporary drugs and pesticides. The chapter cites a total of 192 references, including numerous patents.