The monograph summarises stable-isotope research on massive ice in the Russian and North American Arctic, and includes the latest understanding of massive-ice formation. A new classification of massive-ice complexes is proposed, encompassing the range and variability of massive ice. It distinguishes two new categories of massive-ice complexes: homogeneous massive-ice complexes have a similar structure, properties and genesis throughout, whereas heterogeneous massive-ice complexes vary spatially (in their structure and properties) and genetically within a locality and consist of two or more homogeneous massive-ice bodies. Analysis of pollen and spores in massive ice from Subarctic regions and from ice and snow cover of Arctic ice caps assists with interpretation of the origin of massive ice. Radiocarbon ages of massive ice and host sediments are considered together with isotope values of heavy oxygen and deuterium from massive ice plotted at a uniform scale in order to assist interpretation and correlation of the ice. The monograph is intended for both undergraduates and graduate students, and will assist researchers in geocryology, glaciology, geomorphology, Quaternary geology and palaeoclimatology in understanding of the origin and palaeoenvironmental significance of massive ice.