It is difficult not to regard Dr Bellamy's Tudor Law of Treason as a successor to his Law of Treason in England in the later Middle Ages (Cambridge, 1970), and yet by reason of the much wider range of materials available for the Tudor period it is also a different kind of book. Treason is not an easy subject to write about from the legal point of view. The cases best known to historians are remembered because they were reported for their factual rather than their legal interest. The substantive law of treason seems, moreover, to have been more elastic than the rest of the criminal law. As Maitland said, it is ‘a crime which has a vague circumference, and more than one centre’. There is no contemporary legal writing on treason in the Tudor period which reveals anything like the subtlety bestowed on the private law, and this makes the intellectual history of the subject elusive. Of the practice of treason prosecutions, from suspicion to execution, we know very much more: more, indeed, than we know of mundane criminal prosecutions in the same period. This leads to another difficulty for the historian, that of distinguishing practice and procedure peculiar to treason from English criminal justice in general. We still do not know enough about the latter to be able to draw such distinctions with much precision.