When I joined the New Statesman as books editor in 1996, I had recently edited the Independent on Sunday. The art director (not the present one) remarked, in the tactful way that art directors have, that he had never heard of me. I replied that I wasn't surprised: I had scarcely heard of myself.

Nine years on, including seven of them as NS editor, I still do not flatter myself that I am a celebrity. But I think my name (and my successor's name) is better known to some sections of the print-consuming public than those of several national newspaper editors. The NS and a few other small magazines attract an interest and attention that far exceeds their circulation. Kingsley Martin, one of my predecessors, was among the most famous editors of the 20th century. The Canadian Naomi Klein, of No Logo fame, told me that getting an essay in the NS had impressed her mother more than anything else she had ever done. At least one first-time NS contributor said that, once he had a piece published here, he could die happy.

Something of the same aura surrounds the Nation, of which Victor Navasky has been editor or editor-in-chief since 1978. The Nation is, roughly speaking, our US equivalent, though it was founded in 1865 rather than 1913 and has always kept a greater distance from the Democratic Party than we have sometimes kept from Labour. It also has a more self-consciously samizdat look. As Navasky proudly records, it still prints on paper so cheap ("butcher paper", the Americans call it) that, as someone once said, if you photocopy it, the copy looks better. But until recently, it printed a column by Christopher Hitchens, one of the biggest journalistic stars in the western world. Then Hitchens stormed out, furious at the paper's stance on 9/11 and the Iraq war. John Lloyd left the NS in similar dudgeon for similar reasons. Both received press coverage that is normally reserved for cabinet resignations.

The two magazines have other things in common: both have stayed out of the clutches of big media groups (unlike our rival, the Spectator, for example) and both have spent most of their lives making heavy losses. Navasky used to joke that the Nation had only three profitable years in its history, but nobody could remember which three; and much of this book is occupied with accounts of the struggle to keep it alive. It is a minor miracle of our age that both the Nation and the NS have now moved into profit. This follows a period of about 30 years in which conventional wisdom insisted that, with the expansion of the Sundays and dailies, the rise of alternative media, the decline of the public realm and so on, such publications were anachronisms.

What accounts for their survival and continuing prestige? I would hazard three guesses. First, a small magazine of opinion is more intensively read than bigger and more commercial publications, and this creates a special loyalty among readers, writers and what are euphemistically called "investors". People cut out and keep NS articles and pass them to friends; nobody does that with, say, GQ.

Second, journals such as the Nation and the NS, precisely because they depend mainly on subscribers and not on either casual sales or advertisers, and because they are too poor to pay their contributors properly, are manifestly free of the pressures that bear on most other publications. They command trust and carry authority because readers know that their core content reflects what editors and writers truly believe and think important, and not what the news agenda dictates or what advertisers think appropriate.

Third and crucially, small, independent magazines can consistently challenge conventional wisdom and present an alternative world-view in a way that is impossible for the mass circulation press. This is a difficult trick to pull off, because the danger is that you seem too eccentric and politically marginal to be worth taking seriously. That is why good, traditional, jargon-free English and a fairly straightforward design are so important. In recent years, both the Nation and the NS prospered because they vigorously pushed an unconventional and unpopular view of 9/11 and the Afghanistan and Iraq wars. But much as NS readers and writers may hate to admit it, the most inspirational example comes from the right. Small magazines such as the National Review in the US laid the intellectual foundations for Reaganism and Thatcherism, ploughing a lonely furrow for more than 20 years before (with wretched consequences, in my view) their ideas conquered the world. If the true left is ever to make a comeback, it may have to start in magazines such as the NS and the Nation.

This book - partly personal memoir, partly history of the Nation, partly exploration of journalism and its ethics - has wit, charm, good anecdotes and, for me, fascinating insights into publishing small magazines. It would have been a shorter and much better book if Navasky had not gone into great detail about budgeting, money-raising and forms of ownership. But since I became obsessive about such subjects for seven years - and Navasky is still at it - I suppose I can forgive him.