This cumulative index covers SIPRE and CRREL abstracts 1 to 21,000 which have been published in 17 volumes. The four parts of the work, author, title, patent, and subject indexes supersede the cumulative indexes published in 1955 and 1956. The author index lists the authors of all abstracts produced to June 1963. The title index identifies papers in the above series for which authors are unidentified. The patent index is a listing by subject of all patents abstracted. The subject index consists of approximately four thousand subject headings and cross-references and serves as the subject control for the CRREL Bibliography Project, in addition to its function as a retrieval tool for the reader. The subject coverage for the needs of CRREL and other users is further classified by using topical and geographic subdivisions for the headings. The use of some topics as sub-divisions of other topics has been indicated and crossreferenced as necessary. (Author).