Tax policy questions may relate to specific problems, concerning perhaps the revenue implications of a particular tax, or they may involve an extensive analysis of the cost and redistributive effects of many taxes and transfer payments. This book is concerned with the ways in which tax policy design can be enhanced by the use of a behavioural tax microsimulation model capable of evaluating the effects of planned or actual tax reforms. An advantage of such a large-scale tax simulation model, which reflects the heterogeneity of the population and captures the details of the tax structure, is that it can examine detailed practical policy questions and can provide direct inputs into policy debates. After introducing behavioural models, the authors discuss the role of means testing, several hypothetical policy reforms, actual and proposed reforms and recent modelling developments. Tax Policy Design and Behavioural Microsimulation Modelling will be of interest to academics and researchers of economics, econometrics and public finance. It will also be useful reading for policymakers responsible for the formulation of taxation.