Ian McKellen loves acting so much - is such a purist, in fact - that he disdains the use of electronics, either for his benefit or his audience's. He won't allow microphones anywhere near his stage. He won't permit air cooling, if the sound of the air conditioner is in noticeable competition with his voice. This was one of the creeping surprises the noted British actor presented in his one-man show called ``Ian McKellen Acting Shakespeare'' at the Charles Playhouse here. As the acting heated up, so did the theater, until Mr. McKellen was not the only one mopping his brow. But for a while, nobody noticed the rising temperature, so fascinating is McKellen's material and so winning his performance.
All this is fair warning to theatergoers not only in Boston, where the show continues through Oct. 4, but also in San Diego and Cleveland, the cities McKellen will visit next as he winds up his United States tour.
``Acting Shakespeare'' is partly a kind of living scrapbook of well-known snippets of well-known plays. Because most of the speeches are familiar, McKellen is not forced into lengthy stage-setting as he moves through some 20 characterizations. Without costumes or scenery or props of any kind (save a sturdy chair, upon which he leaps more than once), he makes us ``see'' daggers and scrolls and other actors. There is even a part of the stage that becomes identified as Shakespeare's grave, to which McKellen reverentially returns to remind us that a single person wrote these marvelous speeches and conceived this rich range of characters.
But ``Acting Shakespeare'' is more than an evocation of familiar plays and scenes. Its format includes a running narrative and commentary, delivered with such fluency and unforced enthusiasm that the performance has aspects of an impromptu soiree. Anecdotes, jokes, and judgments tumble out as if momentarily inspired, yet paraded with an unmistakable artistic discipline.
The key word in the show is ``acting'' - a theme running through both the excerpts from the plays and the linking narrative. So we learn of Shakespeare's regard for actors and hear some of the speeches (by Polonius and Hamlet, for example) that expound on the art.
Although the program is mainly a showcase for McKellen's versatility - the wide range of roles he could play brilliantly - the climax of the show is a scene from ``Macbeth,'' performed at some length and brought to a level of extraordinary intensity. Words and theories about acting seemed to fade in the presence of such a demonstration of it.
McKellen won a Tony Award for his performance as Antonio Salieri in the Broadway production of ``Amadeus,'' and was nominated for a Tony for his ``Acting Shakespeare'' show in 1984. He has acted in several films, including ``Plenty,'' with Meryl Streep. Earlier this year he played Platanov in ``Wild Honey'' in Los Angeles and New York, repeating a role he first played in Britain.
Interviewed before the Boston opening of ``Acting Shakespeare,'' McKellen said, ``The atmosphere I'm trying to create is that of a party, in which I'm the host and the audience arrives to meet the guest of honor, who is William Shakespeare.
``Of course, some people in the audience will have known Shakespeare for a long, long time, and they'll be happy to renew his acquaintance - happy to discover he's alive and well. And there'll be other people who only know Shakespeare by reputation, and hopefully they, too, will feel at the end of the evening that it's been worthwhile and that they have been thoroughly entertained.
``That's my aim: to keep a party atmosphere and to convey my own enthusiasm for Shakespeare. I'm not trying to tell anybody anything - not trying to teach anything. Heaven forbid! I'm trying to move Shakespeare from the classroom ... and put him where he belongs, and that is the theater.''
McKellen said he has no major project following his American tour. ``I'm keeping myself free of long-term commitments, so that I can be available to do films, which is really what I hope to do.
``The trouble with me and movies in the past is that I've been under long-term contracts with the Royal Shakespeare Company and the National Theatre in London. And when an offer comes along I have to say I'm not free for another nine months. But I think I'll be doing a film later in the fall, when I go home.''
What is the appeal of film? McKellen quickly cites ``fewer responsibilities.'' On stage, he says, ``when the performance arrives, whether it's a one-man show or not, the actors are in charge, and when the moment arrives, it's just `on with the show.'
``A movie has different problems,'' he continues, ``but you're well cosseted. The director, in fact, makes all the final decisions, and so does the editor, so the actors are just part of the whole machinery.''
The lasting quality of film is another plus, in his view. ``That's one of the nice sidelines of it - as long as the performance is a good one. Of course, if it's not, what could be worse than knowing it was permanently in the archives, in the way that theater isn't!''
McKellen may have forgotten: ``Acting Shakespeare'' is not as evanescent as it may seem after a performance. It is locked up in permanent form as a tape made for public television and used in schools in training future actors.