Twenty liquid fuels and 12 plastic materials from 7 polymer groups were individually burned over 1 hour under controlled laboratory conditions. The soot produced was collected on glass plates and subsequently submitted to a sequence of physical and chemical analyses. In addition, the research considered 12 soot deposits on glass fragments collected from 8 fire scenes in Switzerland and 5 control samples prepared in the laboratory. Results revealed that the combination of physical and chemical parameters permitted the differentiation of most of the laboratory- prepared soot samples. The discriminating power was higher for the chemical analyses; soot samples from plastic materials were the easiest to identify. Nevertheless, microscopy provided interesting information concerning specific soot forms or elements. The combined results allowed the construction of a dichotomic table that can be used for the classification of soot samples taken from fire scenes, although further research is needed before such techniques can be routinely applied. Figures, tables, photographs, and 45 references (Author abstract modified)