High treason - the breach of allegiance which a subject owes to his or her sovereign - has always been regarded as the most serious of all criminal offences. Even today it still carries the death penalty. In addition, all the property of a person convicted of treason was, until the eighteenth century, forfeited to the Crown. Wartime aside, there have been no prosecutions for treason for well over a century and the topic has almost, but not quite, disappeared from legal text books.

In this revealing study, Alan Wharam relates the intriguing stories behind a dozen treason trials encompassing the Earl of Essex in 1601 to ''Lord Haw Haw'' in 1946. The accounts are all based on the reports, believed in most cases to be the verbatim records of the evidence given, and of the speeches of Counsel and the directions of the judges, which appear in the State Trials and other similar works. Some of the cases are famous, some infamous: some, such as the trial in 1781 of de la Motte, the spy, have been forgotten; others, as with the case of Alice Lisle in 1685, have been misunderstood.

Some of the men put on trial were among the most eminent of their times; others, less well known, were acting honourably according to their religious or political principles. As for the conduct of the legal profession, this ranges across the whole spectrum of professional standards: from Sir Edward Coke and Chief Justice Popham engineering the judicial murder of Sir Walter Raleigh in 1603, to Adolphus and Pollock defending men, whose objectives they abhorred, with the highest degree of skill and integrity.

Supported by over forty black and white illustrations, Treason represents a much needed and well-researched account of treason trials in England. It also redresses the balance of a subject little-covered in legal text-books.