Comedy Rules, By Jonathan Lynn

Jonathan Lynn may be best known as the co-writer of Yes Minister (Margaret Thatcher's favourite sitcom, allegedly) but he has also turned his hand to comic acting, directing and screenwriting. Who better to ask, therefore, if you want to write, perform or direct comedy? Surely he'd know what to do and what not to do? Yet this compact and cheerful book isn't just a user's manual. It's also a charming memoir, full of amusing and insightful anecdotes about the many entertainers Lynn has worked with.

By dovetailing different types of book, Lynn cleverly avoids the pitfalls of both genres. Because it's ostensibly a sort of how-to book, there are no boring childhood reminiscences. Because it's also a kind of autobiography, his no-nonsense dos and don'ts are springboards for entertaining yarns, rather than academic discourse. Like all good sitcom writers, "show me don't tell me" is his mantra, as he illustrates his 150 rules with tales from the comedic front line.

Some are simple common sense (though it's remarkable how many people forget them): make the comedy appropriate to the situation; try to insist that drinks and food are not served while you're on stage; beware a phone call from the Inland Revenue, even an invitation to lunch. Yet just as many rules could easily inspire an entire PhD thesis (perish the thought): comedy is objective - tragedy is subjective; the Seven Deadly Sins are present in all comedy; the oldest source of comedy is the Ten Commandments. Probably not quite true, but intriguing all the same.

Lynn's best rules are the ones you never thought of, but make perfect sense when you ponder them: if you start with an absurd premise, you must follow it through with total logic; if the band – or film crew – laugh loudly at a joke, you should probably cut it; topicality doesn't matter – human nature doesn't change.

Comedy Rules is more than a checklist for aspiring comics. Its series of brief but astute biographies linger in the mind's eye long after you've forgotten most of the rules. Lynn reveals relatively little about himself (his breezy writing style is hard to penetrate) but he's a shrewd observer of other people, especially performers. His lightning sketch of John Cleese and Graham Chapman captures the essence of their partnership in a paragraph. His tender portraits of Leonard Rossiter and Jack Rosenthal are remarkably acute. Yet you can sense that, deep down, what matters most to Lynn, like all comics, is laughter.

His devotion to the punchline is encapsulated in a toe-curling account of how he was invited to accept an award from Mary Whitehouse, and ended up watching Margaret Thatcher performing an ersatz Yes Minister sketch. "I'd like to thank Mrs Whitehouse for this award," said Lynn, as he received his prize, "and I should also like to thank Mrs Thatcher for finally taking her rightful place in the field of situation comedy." As Lynn recalls, this impromptu gag made everyone laugh, apart from the PM. "I was never invited back to Number 10 and never offered an honour," he reflects, "but the joke worked."

William Cook's 'Kiss Me, Chudleigh – The World According to Auberon Waugh' (Coronet) will be published in paperback in October