1971 marked the first year since 1956 that the annual Cryogenic Engineering Conference was not held. Instead, the Cryogenic Engineering Conference gave its full support to the XIII International Congress of Refrigeration by working with Commissions I and II of the International Institute of Refrigeration to organize the cryogenic sessions for these two commissions. All of the papers presented at the International Congress of Refrigeration will be published by the IIR as part of the proceedings of that meeting. Even though no Cryogenic Engineering Conference was held in 1971, it became quite evident to the Conference Board that there were sufficient advances in cryogenic engineering to warrant the publication of Volume 17 of the Advances in Cryogenic Engineering. Volume 17 presents the advances in this important field by bringing together in one volume some of the significant papers that have been presented at various technical meetings across the country during the latter half of 1970 and the first part of 1971. In addition, several authoritative review papers have been prepared by invitation of the Cryogenic Engineering Conference Board.