This book deals with a subject that has recently been the focus of debate and law reform in many jurisdictions: how much scope should spouses have to conclude agreements concerning their financial affairs and under which circumstances should such agreements be binding and enforceable? These marital agreements include pre-nuptial, post-nuptial, and separation agreements. The book is the result of a British Academy-funded research project which investigated and compared the relevant law of England/Wales, Australia, Austria, Belgium, France, Germany, Ireland, the Netherlands, New Zealand, Scotland, Singapore, Spain, Sweden, and the jurisdictions of the United States. In addition to these comparative law chapters, the book includes a chapter on the 'English practitioner's view,' an overview of the European private international law rules applicable to marital agreements, and a comparative analysis. In the last of these, underlying themes and principles are explored and recommendations are made for regulating marital agreements. To determine the function and effect of marital agreements, each chapter first sets out the underlying 'default' rules for ancillary relief/matrimonial property and maintenance, before analyzing the current rules for marital agreements, together with a brief account of the private international law rules in each jurisdiction. The book offers guidance for academics and practitioners dealing with international matters and will be a basis for discussions on law reform.