In this paper I collect Richard Freeman’s 1998 War of the Model challenge, and offer a discussion of the “new set of theoretic and empirical tools ” he beliefs will become the “new jargon ” of economic analysis of the 21 st century. In particular, I analyse the main strengths and weaknesses of agent-based computational models. I first describe how agent-based simulations can complement more traditional modelling techniques. Then, I offer a brief review of the most interesting applications in the field. I finally rationalise the main theoretical critiques against the use of simulation, which point to the following problematic areas: (i) interpretation of the simulation dynamics, (ii) estimation of the simulation model, and (iii) generalisation of the results. I show that there exist solutions for all these issues. Along the way, I clarify some confounding differences in terminology between the computer science and the economic literature. Acknowledgements: I’m indebted with Francesco Devicienti, Roberto Leombruni and Bruno Contini for their stimulating comments. Matteo Richiardi – The Promises and Perils of Agent-Based Computational Economics