The most surprising thing about the JG Ballard archive at the British Library, which opened for public viewing on Monday, is that there is an archive at all. More or less up to his death in 2009, Ballard, an intensely private man, had given the impression he'd not kept anything relating to his work whatsoever. In an interview in 1982 he even claimed he threw away his manuscripts. "I hate that instant memorialising," he said. "Little shrines erected in some university library around the handkerchief in which Graham Greene blew his nose in 1957."

In line with his wishes, much of the archive comprises the progress of his texts, which are all here – with a few exceptions – as drafts, manuscripts or typescripts. But there is also plenty of personal and family material: photographs, postcards, faxed interviews. In May I was privileged to have had a sneak preview while it was still being catalogued by the archivist Chris Beckett, partly because I'm writing a book about Ballard. As it's entirely composed of artefacts – Ballard never owned a computer – perhaps this is the last solely non-digital literary archive of this stature.

Notes on Empire of the Sun Photograph: Estate of JG Ballard/The British Library

For Claire Walsh, Ballard's partner, the manuscripts of Crash are the highlights (she objected to her name being used in a first draft and Ballard changed it to Catherine). "The feeling of it being written when it was red-hot in his mind," she says, "and the handwritten changes, I think are absolutely fascinating."

The two typescripts of Crash are in three special black acid-free archival storage boxes, as if they are flight recorders holding the clues to the rest of his fiction. Both are heavily revised by hand – almost violently so – and appear to confirm Beckett's view that he "tended to advance his writing by a compositional principle of enlargement rather than reduction". Somehow far more shocking than the novel's premise of a culture dehumanised through technology able only to connect through the eroticism of car crashes, is that the second typescript has an added exclamation mark – Crash! Perhaps the sustained, willed madness got to him.

For me the most interesting material is the set of five notepads (c 2006-08) that contain Ballard's notes for an unwritten novel that had the working title An Immodest Proposal or How the World Declared War on America, in which a global coalition has reached the end of its diplomatic patience with America's imperialism and makes a pre-emptive strike against it. It's great seeing these gaudy, spiral-bound notebooks with "The Book Store, Shepperton 80p" stickers. Even better are some of Ballard's doodles on the front of a High-Rise typescript, and intriguingly, and also against type, there are notes for a children's story, The Mirror.

Letter from Mary to Ballard's sister Margaret (1964). Photograph: JG Ballard Archive/The British Library

Walsh was delighted to find the notebooks, but is glad they are not all here (he destroyed almost of all of them after each novel was published). "Jimmy kept the early thoughts and false starts private. He wanted to keep his magic," she says. "In between delivering one book and starting another, he used to talk through ideas with me, thinking aloud about where he might go next. Reading the few notebooks in the archive is a moving reminder of this."

There are also quite a few hidden curios, such as the two newspaper cuttings reporting a dramatic incident at the Ballard home in 1959: "Three-year-old Jimmy Ballard and his sister, Fay, two, [were] taken to hospital unconscious after a disused gas pipe fractured in the nursery of their home at The Hermitage, Richmond, today [...] Mr and Mrs Ballard gave the children artificial respiration until the ambulance arrived." Especially poignant – and featuring trademark Ballardian imagery – is one of the two letters written from his wife, Mary, to his sister Margaret, while they were on holiday in Spain in 1964. "We are here for a couple of months and return on the 15th September," she wrote. "The landscape here is arid and barren, sand and scrub and rocks .... Lots of drained rivers which Jimmie (senior) loves haunting." Not long after writing it, Mary died suddenly of pneumonia, and Ballard drove his three children back to England alone.

Beckett, who spent a year archiving the material, says there were some surprises, including a small notepad outlining his novel Millennium People. "It was carefully inserted by Ballard into a single pile of manuscript pages before he tied the bundle with string," he says. "This was unexpected – it was evidence of a deliberate gathering."

There are four of Will Self's letters to Ballard, one of which refers to The Lives of Others. "The film would be worth seeing for the furniture alone," he writes approvingly, "but best of all is that the entire plot hinges upon a typewriter." Typewriters were something both writers had in common (Ballard used an Olympia).

But Self is wary about seeing the archive. "For a fiction writer, it's quite inimical to your own work to be saturated in someone else's," he argues. "He's a powerful and original thinker, and to involve myself in the hypocaust of his imagination is toxic for my own work."

It's hardly surprising that Ballard, this least nostalgic of writers, famously interested in "the next five minutes" as he put it, felt ambivalent about an archive. But then, as Walsh says: "Anyone hoping to find 'the man' from the archive will be disappointed. That was deliberate. He always covered his tracks."