Craies on Legislation is the complete practitioners' guide to the nature, process, effect and interpretation of legislation. It is regularly cited to and by the higher courts, and it is relied upon by lawyers in the public and private sectors for shedding light on the widest range of questions in relation to how legislation is made, applied, challenged and interpreted.

The 12th Edition covers: the classification of primary, subordinate and a growing range of quasi-legislation; the potential of and constraints on all kinds of legislation, including devolved legislation; the legislative process for all kinds of legislation; drafting of different kinds of legislation; explanatory material (including Explanatory Notes and Pepper v Hart); issues of effect from timing and application, the exercise of statutory functions, statutory corporations, effect on other law and errors in legislation (including an account of increasing judicial activism in rectification); the rules, presumptions and canons and principles of statutory interpretation; and a discussion of the effects of EU legislation in UK law.

All recent developments are covered in the 12th Edition including discussion of the developing relationship between legislation and the prerogative, Parliament and the Executive (including Miller 1 and 2 - the Brexit cases), discussion of the latest judicial attitudes to the relationship between legislation and the common law (including the recent Tate Gallery decision on nuisance), and hundreds of other recent cases and political developments (including an account of fundamental changes to legislation in Wales).