OUP is one of Britain's truly great institutions, up there, or nearly, with the NHS and the BBC. As in these other cases, its modern history has been largely dominated by the struggle to preserve its high ideals and standards against the tide of commercialism. As its secretary (chief executive) put it in 1954: "The essence of the Press is that it is not a business."

That is one of the two main themes running through this, the third volume of what is presumably its official history. The other is OUP's spread into the world from 1896 (when its New York office was founded). This suggests that, whatever the outcome of the battle over commercialisation, it didn't damage OUP greatly. In 1970, when this volume ends, it was not only the largest, most diverse and most respected university press in the world, but one of the main agents of British cultural imperialism (in the nicest possible sense), after the formal British empire wearily relinquished that role in the 1960s.

On the surface, this seems extraordinary. For the whole of the 20th century, OUP has been notorious for its antediluvian structure, its vague relationship with Oxford University (of which it is technically a "department"), its governance by a board of academic "delegates", and a "finance committee" that deliberately excluded anyone with business knowledge. It has been widely criticised for its secrecy and cliquishness; its internal hierarchies, described here as "mandarin"; its bosses' restricted backgrounds (nearly all Oxford classicists); its class, gender and anti‑American prejudices; and an apparently amateur approach to all its activities, if "amateur" is defined by a lack of training in "management".

OUP could be slow to embrace the new – paperbacks and computers, for example. The delegates' minutes only started to be typed rather than handwritten in 1969, "94 years", as CS Nicholls archly points out, "after the typewriter was invented". Work always started with morning prayers. OUP considered it infra dig to go touting for authors, instead waiting to be approached by them. It employed some odd people, including a notorious libertine to head its educational sales section; a man who kept "bodily fluids" at his desk; and at least one Soviet agent (Eton-educated) in its New York branch, whose treachery was only discovered as this book was going to press, necessitating a long late footnote by Wm Roger Louis discussing whether this affected his work for OUP (probably not). It was notoriously slow, partly because of the care it put into its editing, which is what made scientists lose patience with it: by the time it was ready to publish their theories, they were out of date. It lost a number of authors because it refused to offer them big enough advances. Some of its books lost money, but deliberately, due to its policies of publishing non-commercial monographs if they were scholarly, and under-pricing to fit the pockets of impoverished academics. "Standards" were not always maintained: a series of "patriotic" booklets it published during the first world war are, frankly, a disgrace; and the deficiencies of its editing of AJP Taylor's otherwise excellent and popular Oxford English History 1914-45 became well known after a famous review by Henry Pelling, listing the mistakes.

OUP has been the butt of witty put-downs from time immemorial – Oxford dons are good at that – although the most famous one is, as Louis points out, a slight misquote: "Being published by the Oxford Press is like being married to a duchess: the honour is greater than the pleasure." (The original had an "almost" before the "greater", which makes a difference.) I have to say – to declare an interest here – that the OUP has done all right by me, both with the book of mine it published, and with one it quite reasonably (as I see now) turned down. But you can understand why some authors were put off.

The reasons it nonetheless flourished in this period are complex. The "honour" – the prestige of its mother university – was a vital one. Authors aren't all money-grubbers, and many preferred the kudos of being published under that venerable imprint to any amount of "advance". They also valued the personal contact they had with their editors, who were cultivated people (sometimes authors themselves). As well as this, OUP did display enterprise in certain crucial areas. For a start, it had a London office – originally just a "Bible warehouse" – which it developed semi-independently into a more commercial scion of the main Clarendon Press in Oxford, publishing works that the latter considered rather beneath them, but which turned out to be the ones that established it as a "general" publisher, rather than a merely academic one. It branched out into children's fiction, for example – Biggles was one of OUP London's – and music. More importantly, it took on English language primers (TEFL) in a big way, rooted in its primacy in the field of dictionaries, and spearheading its "imperial" expansion into the growing second-language anglophone world.

Having no shareholders to satisfy, the OUP could plough profits into new, long-term projects (such as the original Dictionary of National Biography), and cross-subsidising loss‑makers, though this book gives the lie to the common assumption that it was London that subsidised Clarendon. It gave editors freedom to trust their own instincts, rather than utilitarian market rationales; and to wait to find out whether new methods worked elsewhere. It also meant that the OUP was invulnerable to the takeovers and mergers (except on its own terms) that have so unsettled the publishing industry in recent years. It is the only one of my own publishers that hasn't once changed ownership. One of them, in its new hands, seemed to know nothing about books, and didn't even edit mine. One shudders to think what OUP might have become if it had been similarly "privatised". Whether this is enough to allow us forgive it for its elitist Oxford ways is a matter of opinion. I'm prepared to.

This volume stops very abruptly – 1970 was chosen because it was the year of the Waldock report into the running of OUP, which was less critical than some had feared. There are ominous warnings of the storms that were about to hit the publishing world, but no clue as to how OUP has weathered them. That will come in the next volume. Judging by this one, the OUP hasn't emerged unscathed. Careful readers will notice that its printing has been "outsourced" – OUP no longer has its own printing works – and its price is way beyond the means of almost anyone, let alone impoverished academics. So far as production values are concerned, OUP can no longer hold a candle to many American university presses, but this is still an impressive volume – well printed and presented and excellently edited. It also has some gossip. Oxford readers will like that.

• To order The History of Oxford University Press, Volume III: 1896-1970 for £100 with free UK p&p, go to the Oxford University Press website.

• This article was amended on 15 January 2014 to correct a mistake made in the editing process regarding the price of the volume under review.