Starting from the principal-agent perspective, this book offers a new analysis of government. It interprets political institutions as devices designed to solve the omnipresent principal-agent game in politics. In other words how to select, instruct, monitor and evaluate political agents or elites so that they deliver in accordance with the needs and preferences of their principal: the population. This book explores whether there are any evolutionary mechanisms in politics which guide mankind towards the rule of law regime, domestically and globally. It combines a cross-sectional approach with a longitudinal one. Comparing the extent of the rule of law among states, using a set of data from 150 countries concerning political and social variables, the author seeks to understand why there is such a marked difference among states. Taking a state-centred perspective and looking at countries with a population larger than one million people during the post Second World War period, the book examines: The stability and performance of states The conditions for the rule of law regime: economic, social, cultural and institutional ones The evolution of governments towards rule of law Comparative Politics - The Principle-Agent Perspective  will be of interest to students and scholars of comparative politics, government, political theory and law.