This book is a collection of key source materials, mainly case extracts, in the field of constitutional and administrative law. The extracts are preceded by introductory text and linked by a commentary, creating a framework within which wider sources can be studied. The fourth edition has been extensively revised and updated to incorporate recent important judgments. As with the previous editions, the book is geared to the needs of students on modular courses and for that reason devotes itself mainly to extracts of legal rather than political materials to keep the book within manageable proportions. This subject is core for law undergraduates.