The C4 grass Miscanthus × giganteus is of increasing interest as a biomass feedstock for renewable fuel production. This review describes what is known to date on M × giganteus from extensive research in Europe and more recently in the US. Research trials have shown that M × giganteus productivity is among the highest recorded within temperate climates. The crop's high productivity results from greater levels of seasonal carbon fixation than other C4 crops during the growing season. Genetic sequencing of M × giganteus has identified close homology with related crop species such as sorghum (Sorghum bicolor (L.) Moench) and sugarcane (Saccharum officinarum L.), and breeding of new varieties is underway. Miscanthus × giganteus has high water use efficiency; however, its exceptional productivity causes higher water use than other arable crops, potentially causing changes in hydrology in agricultural areas. Nitrogen use patterns are inconsistent and may indicate association with N fixing microorganisms. Miscanthus × giganteus has great promise as an economically and ecologically viable biomass crop; however, there are still challenges to widespread commercial development.