The scope of this volume is intentionally broad. We review applications of spatially realistic occupancy models and age- or stage-structured demographic models as well as individual-based demographic models. These three main Population Viability Analysis (PVA) approaches initially are compared with other conservation assessment tools in an overview by Akcakaya, Lacy and Sjogren-Gulve and Hanski, with a special chapter on plant PVAs by Menges, all using illustrative examples. Fleishman et al. subsequently outline how nested subsets analyses can help discern focal species, taxa whose habitat requirements may encompass those of larger species groups and can be subjected to PVAs. Kindvall then compares the predictive accuracy of simpler occupancy models versus a democratic model for predicting local extinctions and colonizations in a bush-cricket metapopulation. Thereafter, four case studies which use the three model categories are presented (papers by Berglind, Ebenhard, Lennartsson, and Vos et al.). The volume concludes with Gardenfors' paper on the use of PVAs in the classification of threatened species, and Lacy's presentation of the structure and logic of VORTEX, a widely used demographic and genetic PVA model.