The chemical reactions concerned in the preparat,iori of thermosetting resins based particularly on urea or melamine and formaldehyde are discussed, together with the newer cellulose cross-linking a,gents, including cyclic urea-formaldehyde derivatives and non-nit'rogenous compounds, e.g. glycol acetals and epoxides. The effect of ancillary processes on the properties of resin-trea.ted fabrics and the incorporation of addit,ives in the resin bath are reviewed, with particular reference to the production of smoothdrying cellulosic fabrics, and the problems encountered in producing chlorine-resistant finishes are outlined. Newer developments in the fields of water-repellent treatment and durable fleineproofing of cellulosic fabrics are also discussed, and reference is made to the rotproofing of cellulosic materials and t,he production of bactericidal finishes.