Under Ben Barnes, its artistic director from 2000 to 2005, the Abbey Theatre lurched from crisis to crisis, before spectacularly imploding under the combined force of a financial crisis and the disintegration of its board and executive.

This, at least, is the conventional narrative. Ben Barnes has just published his diaries from that time. Already, there has been one letter to the Irish Times correcting a small detail, and in the process painting Barnes as self-absorbed and diffident. The diaries' sprawling size (I have yet to finish them) will be seen as apt metaphor for his ego. The project will, correctly, be seen as being primarily about self-vindication.

So it is ironic that these diaries could prove to be the most enduring and substantial part of Barnes' legacy. He wrote regularly and at length in the white heat of events; this makes for a uniquely intimate, honest and compulsively readable insight into the recent Abbey. Read, for example, his rolling account of Deborah Warner's and Fiona Shaw's production of 'Medea': even as Barnes' appetite for the high-drama antics of this high-maintenance pair wanes, he documents incisively the emergence of their play from the languor of rehearsals to striking international success.

As for the crises themselves, I have a wonkish interest in the detail. And it's all here – the tensions within the board and management; the attempts to lobby corporate and political interests; the pressure-cooker impact of the media; the lunches and drinks and meetings and press conferences and endless faxes and late-night mobile calls –in bewildering, but compelling, 'West Wing'-like detail.

The diaries have the great value of being, apparently, largely unvarnished. Barnes makes mistakes. He changes his mind. He blunders. He openly records his dislike of some people, and his criticisms of the work of others. He feels frustrated and thwarted by the corporate structure he has inherited and the politics of the theatre; sometimes his recording of these is self-pitying, sometimes arrogant, sometimes ponderous. (And, clearly, he can see this himself as he reads back.) But through all this, there is a great, honest passion for the theatre. That passion is channelled into one key ambition: that it produce great art. And produce great art it did; and it experienced the noble corollary, bold failure. There was the spectacular success of Eugene O'Brien's Eden, and the spectacular failure of Sebastian Barry's Hinterland.

There were early tours around Ireland, and successful tours internationally. There was solid groundwork laid for new initiatives in fostering new work and revitalising the institution. There was a vigorous pursuit of improved facilities for the Abbey. (If the Abbey ultimately moves to George's Dock, and is successful there, the groundwork will have been laid by Barnes, who created the climate in which relocation to the Docklands became politically acceptable.) And yet, and yet. In one two-week period early in his tenure, he finds himself in Belfast, London, Berlin and St Petersburg. He obsesses with the ephemeral project of linking the Abbey "with Europe". He takes on outside work, which involves more long-haul travel. He gets sick. He seems concerned more with an abstract international public than with the one on his doorstep. He displays elitist disregard for a wider public that doesn't patronise his theatre, and consistent contempt for a Fourth Estate which, for all its failings, makes some attempt to tell the Abbey's story to that public. He makes passing comments about budgets, but displays no passion for investigating that side of the operation (to be fair, his role and access to information on the administrative side seems to have been greatly circumscribed by the corporate governance structure). Even as his honest and ambitious ideas for the Abbey trip over themselves, the diaries scream out: hubris!

And so they plough on with the grim inevitability of Greek tragedy. Barnes is a good but flawed man, in a troubled world. He overreaches, and stumbles, and the fates lead him on, relentlessly, to his downfall, while the media chorus taunts him.

But with his downfall comes the possibility of renewal for his world. Its sins are expunged; those who are left behind can start over. It all had to happen; it's just a shame that it had to happen to a noble fellow. But that's drama, and Barnes, if anybody, should understand that.

'Plays and Controversies. Abbey Theatre Diaries 2000-2005', Ben Barnes, Carysfort Press, €25