Volume II/17 c is the third part of a supplement to the pre-vious compilations II/1 and II/9 a-d2 on magnetic propertiesof free radicals published in 1965 and 1977-1980, whichcovered the literature up to 1975. Due to the still veryrapid development of the field and the inclusion of new sub-jects, the supplement covering the period 1975-85 had to besplit into subvolumes, which will appear in fast succession.Togetherwith the ealier volumes, II/17 offers an up-to-dateand comprehensive surveyand a collection of data on impor-tant chemical intermediates.