In an era rich with radical ideas and literary enterprise, the family of Percy Bysshe Shelley remains a uniquely impressive group of individuals. Shelley, the poet of Ozymandias and Prometheus Unbound, a passionate intellectual, was expelled from Oxford to lead a meandering, impoverished and tragically curtailed life in Europe.

His wife, the equally impressive Mary Shelley was the author of Frankenstein, one of English literature’s most enduring works. Her parents were the philosopher William Godwin and Mary Wollstonecraft, an early feminist. “These were all very original, quite radical thinkers,” said Stephen Hebron, whose book, Shelley’s Ghost: Reshaping the Image of a Literary Family, charts the history and correspondence of this talented clan. “Shelley, Godwin and Wollstonecraft were interested in the betterment of society through writing and intellectual endeavours. It wasn’t airy-fairy. It was grounded in society, what they wanted society to become and how it could improve.”

The book accompanies a Bodleian Library exhibition which he has curated. The library acquired manuscripts, correspondence and relics belonging to this illustrious family from Percy Shelley’s daughter-in-law, Lady Jane Shelley, at the end of the 19th century. Other items, such as Mary Shelley’s original draft of Frankenstein — including revisions in the margins suggested by her husband — arrived more recently: the Bodleian bought this in 2004 for £3.9m.

Hebron, who has also overseen several exhibitions at Wordsworth’s Dove Cottage in the Lake District, said the archive of Shelley’s notebooks, full of doodles, sketches and fragments of verse, or William Godwin’s diary — where he laments the death of his wife, Mary, who died giving birth to Shelley’s later wife — was full of revelations. “I had never really looked at Shelley’s notebooks before; obviously, the Frankenstein manuscript is fascinating, as are Mary Shelley’s journals. These are things that are wonderful to look though and get a feel for. The interest is partly what’s in them, the intellectual content of them, but they are also strangely evocative. They have this ability to evoke past lives. It is their tangibility. To handle them or even to just see them through glass; they are excellent things to view.”

Biographies already exist of the literary luminaries, but the book concentrates on the history of the archive as much as on the people themselves. It tells how Mary Shelley, tortured by the loss of her husband, chose to enhance the public’s appreciation of him, as well as that of her parents, by the selective publication of manuscripts, and the suppression of others. The same happened when the archive then passed to her son, Sir Percy Florence Shelley and his wife, Jane.

“Lady Shelley guarded the archives extremely closely — not always in a laudable way. but it’s interesting that she felt the need to do that. You could say that if you own a great literary archive like that it doesn’t really entitle you to say the last word about aspects of people’s lives and stop independent scholars looking into things by not allowing people to see all his manuscripts. Certainly from today’s point of view, that is not what you would expect.”

Eventually, however, she did relinquish much of the archive to the Bodleian in 1893-4. The relationship between Percy and Mary Shelley was, naturally, of great interest. The poet left his first wife, who later committed suicide, before eloping with Mary to Europe. Two of their children died and Shelley himself drowned in Italy at 29, so it was a highly tumultuous, and ultimately tragic, union. “It was a happy marriage, although it certainly had its strains, from all the travelling around, Mary’s depression and Shelley’s highly unusual lifestyle and way of thinking. But they remained devoted.”

They saw each other as ‘intellectual equals’, but although Mary wrote the far more commercially successful work, Hebron maintains that Shelley was never eclipsed by his wife. “In terms of their literary stature, Shelley is recognised as a great poet.”

But what would the great poet who was expelled from Oxford (for writing the essay The Necessity of Atheism) make of his disapproving alma mater holding this exhibition celebrating his genius? Would a wry smile form on his lips?

“It’s difficult to know,” says Hebron with a laugh. “He never really talked about Oxford much, after he left. It was traumatic at the time: it led to a very unsettled existence, but he doesn’t seem to have borne a grudge.”

* Shelley’s Ghost: Reshaping the Image of a Literary Family is published by the Bodleian Library at £19.99. The exhibition runs until March 27.