Abstract As conventional crude reserves approach their predicted peak production as early as 2030, unconventional resources such as heavy oil and bitumen are receiving increased interest and are driving the more abrupt development of exploration, in-situ technologies, and prospective markets. For the first time, the huge potential of Russia’s vast heavy-oil and bitumen reserves is beginning to undergo systematic assessment, particularly in the eastern Siberian platform. Siberia’s natural bitumen fields have historically been disregarded and continue to be underrepresented in production markets mostly because of the climatic and technological challenges associated with in-situ extraction from permafrost and their extreme geographic distances from existing production and transportation lines. Until recently, much of the Russian literature has not been readily available. The compilation of references from western literature of this chapter, along with U.S. Geological Survey collections of Russian translations, will hopefully renew the interest of western researchers in these unconventional hydrocarbons. Geochemical studies presented in this chapter point to a different model for the emplacement of hydrocarbons in the Olenek uplift, which suggests that hydrocarbons are likely derived from the paleo-Verhhoyansk Basin to the east. These refined geologic and geochemical models, along with improving infrastructure and the potential for integrated development of the unconventional resources, open up the possibility of significant future production in Eastern Siberia.