Brian O’Nolan, AKA etcetera etcetera, was so private, and so privately unassuming, a personality in his time – or so elusive and shape-shifting, if you like – that few of us know anything about him beyond the barest biographical detail. The outline goes something like this. Three brilliant novels in roughly as many years. The two that are published in his lifetime are only minor commercial successes but acclaimed by a corps of literary worthies. No matter that his books haven’t made him a fortune – he has a steady civil-service job and a cushty columnist gig which gives him not just a good income but daily and instant creative satisfaction the envy of any artist. Then in the final years more widespread appreciation and a couple of late novels which, alas, come as his health rapidly declines.

A new, monster collection (603pp) of O’Nolan’s correspondence, edited by Maebh Long for Dalkey Archive Press, puts a lot more shading on the life of the hydra, and in places it’s almost pitch black. In accumulation the collection reads as a life of struggle – against illness, employers, various ingrates and nincompoops, and, unexpectedly, the author’s self-opinion. It’s ultimately depressing, although in sequence it manages to be hilarious, for O’Nolan’s polychromatic humour – knockabout nonsense, ludicrous observation, spluttering invective, spot-on satire, and a fabulous line in self-deprecation – colours almost every communication.

It’s also, it almost goes without saying, an enlightening collection (although O’Nolan was such a habitual performer, even to close friends and associates, that the absolute truth remains undisclosed). We learn, for example, of some of the books that influenced the young writer (the works of JW Dunne, and, if confirmation were needed, The Crock of Gold by James Stephens), and there are eyebrow-raising words on Austin Clarke and Brendan Behan. I’d known well enough that O’Nolan’s novels met with a mixed critical reception, but what I know now is that his editors and agents could be sniffy too about his work. Even the early acclaim of one or two of those big-name writers was qualified and, in any case, given what the letters show us about his own insecurities and cynicism for the anointing hand of others, wouldn’t likely have buoyed him anyway.

‘I guess it is a bum book,’ he writes to the American playwright William Saroyan, on At-Swim-Two-Birds’s early failure to find a readership. Which might be taken as humility until put together with the dozens more examples of self-excoriation, or with this statement, twenty years later, ahead of the novel’s republication: ‘I must confess that I have personally no faith in the book but I realise that its true worth is quite irrelevant’, or with this, a little later, in 1961: ‘I regarded the book as juvenile trash.’ But Graham Greene loved it, right? He did, yes, but it’s not the full story. A note on the manuscript from the then young reader at Longman’s, reproduced in a letter from O’Nolan’s agent Andy Heath, quibbles that it is ‘at times unnecessarily coarse, and a few passages could be cut without harm. Otherwise its only fault seems to me an obscure and rather hurried ending, and a title far more difficult than anything in the book.’

The struggle continues post-Swim, with the rejection by Longman’s of The Third Policeman (‘We realise the author’s ability but think that he should become less fantastic and in this new novel he is more so’), which, if O’Nolan himself is to be believed, must have come as a blessed relief (‘I feel, no fooling, that I’ve made a mess of the thing…’). An Béal Bocht, the novel that followed, received this reader’s report from Browne and Nolan: ‘For want of knowledge he cannot begin, or continue or finish a sentence properly. Constructions such as he writes have never before been seen in Irish, and one earnestly hopes that nothing of the kind will ever be repeated.’ And how about this from Sean O’Casey for mealy-mouthed praise? ‘Anyway, thanks again for sending me your cleverly written book [An Béal Bocht]. I wish it every success.’

How did O’Nolan go on writing in the face of such self-doubt, indifference and downright hostility? Duty, of course (to The Irish Times), compelled him, but also the need to hustle for extra cash – surprising, to me, given what I’d assumed was the security of his double occupations. Hustle, hustle, hustle is the abiding theme of this collection: hustling to press his books into a potentially kind reader’s hands; badgering various outlets to publish his work; beating down the door of Irish Times editor Bert Smyllie for increased pay; touting his talents here and there (‘Dear [Director of Radio Eireann], I would be obliged if you would send me application forms in connection with the vacancies advertised on March 15 for: i/ Station Supervisor ii/ Programme Assistant iii/ Balance and Control Officer’). And did I dream it, or did he try to get himself elected to the Seanad? No; I flick back and it’s there in a letter dated March 1957 to the electors of the National University constituency. (He received just 389 votes, the lowest number, a footnote tells us, and was unelected.)

A key feature in all these letters is their intelligence – the ‘fierce intellect’ a sozzled O’Nolan boasted to Tim Pat Coogan in a famous TV interview – which seems a platitudinal thing to say about a genius. But what I mean is they bespeak a man with not just latent brilliance and good tact, but the conditioning of his times and circumstances – schooling in Latin and therefore clarity of thought, and daily immersion in the civil servant’s language of transparent semantics. They’re crystal clear and precise in effect, they’re ornate when they want to be and vulgar at just the right moments (it’s always bracing to see the word ‘cunt’ in a seventy-year-old letter), and they’re sometimes deliberately long-winded in a way that would make a parliamentary obstructionist proud. The latter strategy is breathtaking when used on the attack. In a 1953 letter to Minister for Finance Sean MacEntee beginning, ‘I am impelled to address you personally regarding my recent disappearance from the civil service…’, the sentences clack forward on caterpillar tracks. It’s marvellously impassioned yet level-headed.

Another notable feature in the collection is the startling lack of engagement with current affairs and geopolitics. With his eyes trained on the bathetic quotidian and his head filled with the loftiest thoughts, it seems that there wasn’t much given over to the stuff in between. Notwithstanding the likelihood that many of O’Nolan’s letters remain hidden away (as Long admits in her introduction), the dozens of letters reproduced from the war years barely mention the conflict, except, and only fleetingly, with regards to how it inconveniences O’Nolan. What’s frustrating about this is we know from his passport stamps that O’Nolan spent a month in Germany in 1936, and so was obviously a witness to life in the Third Reich. In 1943 there’s an allusion to his role as secretary to the Cavan Fire Tribunal, the official investigation into the deaths of 35 children and one adult in an orphanage blaze; presumably O’Nolan would have been privy to the most harrowing evidence, yet no record of his thoughts on the disaster are in the letters. Between 1956 and 1960, O’Nolan and his wife Evelyn lived at 10 Belmont Avenue, Donnybrook (which is incidentally the subject of amusing correspondence over cowboy tradesmen). A check on Google Maps will reveal that the infamous St Mary’s Magdalene Laundry was close to the rear of it. Of course, O’Nolan could only have guessed at the horrors over his back wall, yet it’s intriguing that he didn’t even guess at them in his letters.

The three identities of O’Nolan – the man himself, Flann and Myles – are in evidence, but usually all braided one around the others. Early letters to The Irish Times pricking the pomposity of Sean O’Faolain and Frank O’Connor (the same letters that convinced editorial staff to give O’Nolan a regular gig), are signed ‘Flann O’Brien’, are a dry run for Myles, and are probably the only ones written consciously in guise. As I mentioned above, O’Nolan was a helpless performer, so even business or friendly correspondence is striated with Flann trademarks; vide ‘Reading between the lines as well as along them, it seems to me that you are in good form’ to William Saroyan; or this, in relation to a byline photograph needed for an article in a trade journal: ‘I wonder would you search your biblical treasures to see have you a woodcut type of portrait of some old bollox with a filthy fungoid plaster of beard on him full of dandruff and earwigs.’

By far the most interesting of the three identities, for the little we had on him up to now, is Brian O’Nolan himself. For this reason my star letter award goes to the one from which the extract below is taken, for it demonstrates O’Nolan trying to be plain-speaking yet fulminating with frustration, with the consequence that Flann comes breaking through the fissures. It’s a letter of complaint to Underwood Business Machines about an IT problem, and, in its reference to dicky machines and human stupidity, is an irresistible evocation of The Third Policeman:

‘A few weeks ago the ribbon [on my typewriter] stopped moving; I rang up your Dublin branch and asked them to send out a man, which they did. I told them that in addition to fixing the ribbon, I wanted him to clean up the machine generally (the entire inside was filthy from the debris of erasures), and to oil all moving parts. He was in the house for 15 minutes. The ribbon movement, I found later, had been restored, but no cleaning or oiling had been done. I found the machine now had a fault which it did not have before the “repairs” – a misalignment of a capital initial with the rest of the word in lower case, plus a tendency for a double-space turn to become a treble space. I concluded that whatever the mechanic had done about the ribbon had caused some amassed dirt to get deeper into some working parts… Advertisements are continually appearing in the press here, as elsewhere, suggesting that efficiency is not possible [unless] people use Underwood machines and services. This small transaction may make you wonder what sort of damned nonsense is going on in your Dublin office.’

About half the book is taken up by letters written in the 1960s, or the final five-and-a-half years of O’Nolan’s life. The increase in correspondence might be partly explained by the fact that, when O’Nolan was relatively hale and mobile, he had no need to be sending letters to Dublin acquaintances when he could meet them in person. But the booze was catching up with him now, and an alarming number of letters in these years show various health facilities as the outgoing address, or else are written in a state of respite at home. The biographical timeline details seven motor accidents, four of them taking place in the five years 1958 to 1963. The ailments mount too: bronchial pneumonia, infections, food poisoning, and there’s even talk of syphilis.

These were not easy years, in any way. Although there was something of a late creative splurge, the last novels were badly received in comparison to the belated universal admiration for his earlier works. Philip Larkin, in his Guardian annual review, nailed exactly how The Hard Life is perceived today by stating that, while the book was his biggest disappointment of 1961, it was still superior to a success by most others. A large proportion of the later letters relate the gestation difficulties of The Dalkey Archive (‘I am not so sure about the quality of this farrago of geophysics, Einsteinian energy, theology, hagiography and booze…’; ‘I know some of the writing is deplorable for a man of my pretences…’). When the verdict on his last novel arrives from the professionals, it’s chilling. Any writer who has dealt with such people will shudder at the way O’Nolan’s agent Timothy O’Keeffe starts his 22 October 1963 letter with, ‘You asked me to write about the typescript, which I do in complete and faithful honesty.’ And then – talk about kicking a man when he’s down! – this from Cecil Scott of Macmillan in New York: ‘For a man who has had two operations and has been in hospital, in and out, for the last two months, this letter, I am afraid, may seem unnecessarily harsh, but…’

He must have been so weary now, and he was. But the humour continues to glint through, even though – even more so than with the earlier letters – you suspect it was performative. ‘My dear Dorine, my darling, Lying on my mattress here and reading your charming letter, do you know what my unstable mind began wondering about? Whether matress [sic] is the female of Mater.’ He had five months of life left in him, but all the glory was still to come.