This is the first book in the new series Constitutional Systems of the World, and as such launches what is set to become an invaluable resource for all students and teachers of constitutional law and politics. The book provides an outline of the principles and doctrines which make up the United Kingdom constitution. The chapters are written in sufficient detail for anyone coming to the subject for the first time to develop a clear and informed view of how the constitution is arranged and how it works. The main themes include: a description of the history, sources and nature of the constitution; later chapters deal with: constitutional principles, the role of the Crown, Parliament and the electoral system, government and the executive, the constitutional role of courts including the protection of human rights, the territorial distribution of power between central, devolved and local government and the European Union dimension. Secondly, the book offers an analytical discussion of the development of the constitution, its strengths and perceived weaknesses, and the on-going reforms aimed at modernising the UK constitution. The book is written in an accessible style, with an emphasis on clarity and concision. It includes a list of references for further reading at the end of each chapter.