The established federal polities in the world have evolved over decades and centuries, through political upheavals and wars, through continual pressures that tug towards more centralization and then pull towards greater local autonomy, and through their capacity to morph and change to new circumstances and challenges. In response to internal demands and external forces, federal polities have adapted to these pressures by rewriting constitutions and laws, engaging in civil disobedience and violence, establishing fundamental human rights, revising fiscal systems, reconfiguring programmatic and service-delivery responsibilities, and in all other manner negotiating and bargaining in order to sustain the strengths of the federal system over time. Indeed, understanding how federal systems have adapted to changing environments over time and how they have adjusted to myriad challenges provide important insight into reform efforts in the political world today. This book highlights two important factors in understanding federal structures and the choices that polities might confront as they are challenged to re-adjust and re-align their political systems. One is the effects of the passage of time and historical events that condition the political, legal, fiscal and policy environment of federal systems; the other is time's related counterpart, change and federal systems' responses and adaptation to fluid political situations.