This became the guiding principle of Humphries' life. His mother - a product of the genteel zone of Melbourne, a woman who maintained a domestic servant simply as 'an indispensable example of incompetence and slovenliness' - was an easy first target. As a pre-pubescent, the spoilt Barry would innocently say that he was leaving the Sunday lunch table in order to 'strain the potatoes'. When Mrs Humphries asked what he meant, he explained that he was going to 'point Percy at the porcelain'.
At university, Humphries became intrigued by Dada and engaged in performance art. His favourite endeavour was to get a friend to pour a tin of Russian salad, a vomit lookalike, on a busy pavement. Moments later the Dadaist himself would arrive and terrify passers-by as he gobbled up the roadside pool.
It was in the Sixties, when he first arrived in London - brilliant, iconoclastic and on the verge of alcoholism - that Humphries was most determined to shock. He went on a decade-long self-destructive jag. Regardless of the consequences, he could not pass a woman without putting his hand on her knee, nor pass a pub without drinking it dry. Yet somehow everytime he leapt over the precipice, the bungee bounced back. He emerged from his alcoholic darkness, which culminated in a long spell in mental hospital, with his principles intact. Now in the sober guise of Dame Edna Everage, on prime-time television, he can say things like 'my gynaecologist often compliments me on my interiors'.
A story like Humphries' should be dynamite in anybody's hands. Oddly, he himself chooses to tell only half the tale. It is no surprise that he tells his half with skill and humour, given his rare ability with words. This is how his character Barry McKenzie once ordered rare filet mignon: 'Just knock off its horns, wipe its arse and bung it on the plate, garcon.' And here he proves that he can write a joke almost as well as he can tell one: 'A doctor told me that my liver was inflamed and asked me how much I drank. It was a difficult question to answer. Did he mean, for example, before or after breakfast?'
The problem with the book is not how much it reveals, but how much it conceals: More Please is an apt title. Although he does not indicate it, this feels like a first volume; it ends with Humphries cleaning up his act in the early Seventies, before that act became world famous. We are justified in asking for more, please, about the grime, and fewer adjectives about his childhood. More, please, about how he felt while he was in the gutter of alcoholism, and less jolly whitewash like this: 'I was ready for the short stroll from my flat to the Red Lion, which, miraculously, threw open its doors at the precise moment of my arrival.'
Drifting through the Sixties in an alcoholic stupor doesn't do much for the memory, and on several occasions he says that he can't actually remember what happened. But too much of the hurt has been excised from this account. On stage, we are used to seeing Humphries hide under a carapace of Dame Edna or Les Patterson; here he wears a disguise of upbeat good humour. The self-revelation, when it comes, is too pat: 'Roslyn was a beautiful girl from Sydney who deserved a great deal better than the sporadic companionship of a dissolute, guilt-ridden, self-obsessed boozer, whose own definition of himself would have been very different.'
According to his friend C K Stead, going out for an evening with Barry Humphries in the middle of the Sixties was like watching 'someone go over Niagara Falls in a barrel and survive'. That probably tells you more about the Dame than anything else in the book. And it isn't even her line.