As a character in Tom Stoppard’s play, Rosencrantz and Guildenstern Are Dead, so gloriously puts it: “We’re actors, the opposite of people.” Reading The Making of the Professional Actor you are constantly reminded that actors are, and have been throughout the ages, a breed apart.

Why else, you ask yourself, would any professional person put up with the indignities of the career Cairns describes? There are long periods of unemployment - at any one time more than 80 per cent of Equity members are out of work, and the rules have been tightened to dissuade actors from claiming unemployment benefit - and when work is available the wages are paltry, currently Pounds 180 a week in repertory theatre. All this for the glory of appearing in an episode of a television soap or the riches that a 30-second commercial brings.

But, as Cairns rightly points out, the big break is always just around the corner, and thousands of young people are entering the ever-growing number of acting courses that have sprung up around the country, lured by the prospect of fame.

Cairns has written a comprehensive, well-researched book; not a guide to becoming a professional actor, but a book aimed at students who wish to follow the path of classical training. For the drama teacher it is an invaluable aid, charting the history of acting from medieval times through the Elizabethan and Restoration periods, the 18th and 19th centuries, up to contemporary Britain, Europe and the United States.

It will also be of interest to anyone involved in the debate over grants for drama students, where parallels can be drawn with the status of actors in the past. Cairns, in his work as a lecturer at the Bristol Old Vic Theatre School, is well placed to see that, unless grants are awarded for vocational courses, students will be accepted not on the strength of their talent, but for their ability to pay the fees.

The drama teacher who is dismayed at the current emphasis on the academic as opposed to the practical in the syllabus will be interested to read: “It is economically convenient to treat drama as literature, and to think that it can be adequately studied as part of a literary curriculum. It is not literature, nor can it be taught as such. To believe it can is like believing you can teach surgery by taking a general course in biology.” That was written nearly 30 years ago by one of Britain’s great actor directors, Tyrone Guthrie.

Looking to the future, Cairns offers some thought-provoking ideas which depart from conventional attitudes. Will we one day have our own virtual reality headsets where we can employ an actor in a scenario of our choice?

The Making of the Professional Actor offers a wide-ranging assessment of the theatre and should be read by everyone involved with drama training, be they teacher, student or policy-maker.

There is no doubt where Cairns’s sympathies lie in his appreciation of the theatre. He sums it up in the words of the director Peter Hall: “A good theatre company is a metaphor of a possible society.”