This book offers researchers a new and emerging population analysis tool, allowing for more flexible strategy in sampling data. Leading ecologists provide insight into combining two complex models and using a simplified unified model (referred to as a hierarchical or state-space model). This new approach yields surprisingly simple solutions to some very complex problems. Examples include: (1) Hierarchical models of simple counts (2) Modelling individual heterogeneity in capture-recapture models (3) Estimating community structure by modelling occurrence of species