You wouldn’t expect a 1,300-page textbook on criminal law to make for light bedtime reading.

Glanville Williams’s magisterial Textbook of Criminal Law, however, is not just any textbook.

Originally published in 1978, and updated in 1983, it is on a US list of the most cited legal textbooks of all time.

It is hugely informed and authoritative. But what puts it head and shoulders above other legal textbooks is the style in which it is written.

The textbook takes the form of a series of questions (sometimes slightly irreverent) and answers – almost like one of Plato’s dialogues. Williams introduces a point of law, questions it, and answers the questions in language that is always clear, and often humorous too. He challenges the law, rather than simply explains it. At one point, discussing the development of the law, he asks: “So the judges concoct the law as they go along?”

His answer: “That is an exaggeration, even though it has a considerable measure of truth. It is an exaggeration because judges tend to be conservative and traditional. They like to think of themselves as administering a system of law, not merely… justice under a palm tree.”

Discussing the issue of life sentences for those convicted of murder, he asks; “What about the barmy ones? Must they too be sentenced for life?”

His answer: “Yes, if they are convicted of murder; but they will not be. A mentally disordered defendant (note the proper expression) can in appropriate circumstances set up either an insanity defence…or a defence of diminished responsibility…”

Williams died in 1997. But his book – which covers all the major areas of criminal law – has now been thoroughly updated by Dennis J Baker, a lecturer in criminal law at King’s College, London, to include material on the European Court of Human Rights, and to bring the chapters on sexual offences, fraud and provocation up to date.

Baker has managed to capture William’s unique style. And the joy of the book, says the Cambridge Law Journal, is “in the judicious blend of learning, clarity, insight, irreverence, humour and humanity”.

So no, not bedtime reading. But if you want to know about the workings of British criminal law, you won’t find a more informed, authoritative or accessible guide.