Rushdie begins this second collection of essays with a brilliant 30-page take on The Wizard of Oz ("that great rarity, a film that improves on the good book from which it came"), a film "whose driving force is the inadequacy of adults, even of good adults".

This is followed by nearly 70 shorter essays on subjects as diverse as censorship, photography, rock music, leavened bread ("East was East, but yeast was West"), adapting for film ("the rejection of Midnight's Children changed something profound in my relationship with the East"). The section also includes the heat-and-dust-raising essay with its controversial thesis that post-Independence fiction and non-fiction by "Indian writers working in English is proving to be a more interesting body of work than most of what has been produced in the sixteen 'official languages' of India, the so-called 'vernacular languages', during the same period."

Rushdie's gimlet eye also takes in, among others, Angela Carter, Arthur Miller, and Gandhi ("fifty years after his assassination, Gandhi is modelling for Apple…. Gandhi today is up for grabs").

The first section ends with "A Dream of Glorious Return", a diary of his June 2000 visit to India with his son: "This, perhaps, is what it means to love a country: that its shape is also yours, the shape of the way you think and feel and dream. That you can never really leave."

"Messages from the Plague Years" follow: selections from his published pieces on the so-called 'Rushdie affair' of which he said in an interview on Salon.com: "I think it's a bad Salman Rushdie novel. And, believe me, it's a very dreadful thing to be stuck in a bad novel." In these pieces Rushdie both directly campaigns against Khomeini's fatwa ("the appalling Valentine I was sent in 1989"), and writes eloquently on "a Sarajevo of the mind, an imagined Sarajevo whose present ruination and torment exiles us all".

On 24 September 1998, Rushdie tells us, during the UN General Assembly in New York, the foreign ministers of UK and Iran issued a joint statement that effectively brought the fatwa to an end.

But, as he asks in the next section of these essays, "How can I explain to strangers my sense of violation? It's as if men wielding clubs were to burst loudly into your home and lay it waste. They arrive when you're making love, or standing naked in the shower, or sitting on the toilet, or staring in deep inward silence at the lines you've scrawled on a page. Never again will you kiss or bathe or write or shit without remembering this intrusion. And yet, to do these things pleasurably and well you must shut out the memory."

The brief essays of this third section were syndicated columns in the New York Times. They engage with current issues: political, social and cultural. To all these Rushdie brings a sharp mind and devastating humour. Excerpts:

"Pakistan": Zia promised and cancelled elections so often that it became a joke. His title in those bad old days was CMLA, which officially stood for 'Chief Martial Law Administrator', but which, people began to say, really stood for 'Cancel My Last Announcement'.

"God in Gujarat": The murder of children is something of an Indian speciality.

"Moron of the Year': [Charlton] Heston thinks America should arm its teachers…. (Little Johnny reaches into a pocket for a pencil -- and Blam! Blam! his geography teacher blows him away.)

"Sleaze is Back": I knew a man once whose thing it was to wreck the toilets in office buildings and write a slogan on the ruined walls. 'If the cistern cannot be changed it must be destroyed.'

And in the concluding pair of essays -- his Tanner Lectures on Human Values at Yale -- he asks the audience's permission to "mention the word, Harvard". These essays that give the book its title are a meditation on frontiers: "for all their permeability, the borders snaking across the world have never been of greater importance."

Back in 1983, in an interview with T Vijay Kumar, Rushdie spoke of his decision to "do something very dangerous" which was to write Midnight's Children. He has continued to do many dangerous things, and in the process, as he says of J M Coetzee, added "to the sum total of the imagined worlds at our disposal, and by doing so, increased what it is possible for us to think". These essays should be read and reread to protect us from what Rushdie's mother would have called "forgettery".