This index is a cumulation of the annual subject indexes to five volumes of the Bibliography on Cold Regions Science and Technology (43-47). In anticipation of this cumulation (and the companion Author index) the annual indexes have been bound separately rather than with the bibliography volumes, so they now may be discarded. The index is arranged alphabetically by subject. Two kinds of subject terms are included: those contained in an authority list, and free terms used as needed, without vocabulary control. This duality of indexing principle results in a somewhat uneven frequency distribution of terms. Geographic terms are also included, generally by country. The subject (or geographic) terms are followed by the title of each pertinent article (original, translated, or modified for conciseness or detail), listed by accession number. The title is followed by the principal author's name, the year of publication, the pagination, and the language in which the paper is written (in the case of translations, English is given as the language). The accession numbers listed after each index entry refer to the Bibliography section of the Bibliography on Cold Regions Science and Technology. The first two digits represent the volume number; these are followed by a hyphen and the sequential number within the volume.