Data collected in the social sciences often have a multilevel or clustered structure. From this, we often have research questions that are of a multilevel nature, and multilevel modelling is now widely used across health, economics, demography, education and many other areas to analyze data clustered within units at higher levels. The editors of this essential four-volume set, Multilevel Modelling, are among the leading figures of multilevel modelling, an approach which is at once cutting-edge and well established within research methods and the social sciences. Volume One: Linear Multilevel Models: Model Formulation and Interpretation Volume Two: Linear Multilevel Models: Inference, Diagnostics and Design Volume Three: Multilevel Generalized Linear Models Volume Four: Complex Models and Issues