Her book was selected as the winner by a celebrity judging panel, as well as by readers from five Waterstone's reading groups.
Guardian literary editor, Claire Armitstead, who chaired the judging panel, said: "At a time when universities are threatened as never before, Alexandra Harris's ground-breaking book is a reminder of how important higher education is to literature, and to culture as a whole, and how crucial it is that the finest young thinkers have the time and space to develop.
"I'm excited that the judges decided to make what one of them described as 'counterintuitive decision' in choosing this book as the winner. Serious works of art history rarely win populist prizes, and often have trouble finding publishers at all. Yet the response from our Waterstone's reading groups, as well as from our central panel, showed that readers of all sorts are willing to engage with demanding books, if they are well written and beautifully produced. I know we will be hearing a lot more from Alexandra in the future."
Novelist and poet Adam Foulds, who was on the judging panel, said: "This book was my top choice. It's a brilliant piece of work that manages to be both comprehensive and coherent as it tells a compelling story about twentieth century English art and its preoccupation with place and particularity. As I read it, as well as learning a great deal, I had the sensation of lots of scattered things I was familiar with joining together and being illuminated in a new way. It is beautifully written and strikes me as a significant contribution to the history of English culture and one that people will read and return to. This book has a long life ahead of it."
Harris wins £10,000 and an advertising package in the Guardian and The Observer, and follows in the footsteps of Zadie Smith and Jonathan Safran Foer, two of the previous winners of the Award. Last year's award was won by Petina Gappah for her short story collection, An Elegy For Easterly.
The Guardian First Book Award is open to all first-time authors writing in English, or translated into English, across all genres. Established in 1999, the award aims to recognise and reward the finest new writing talent for an author's first book.
Waterstone's reading groups to help judge the longlist were set up from their branches in Oxford, Bath, Manchester, Covent Garden and Edinburgh.
The 2010 judging panel comprised of Claire Armitstead (Guardian literary editor), Adam Foulds (novelist and poet), Richard Holmes (biographer), Diana Quick (actress), Ekow Eshun (executive director of the Institute of Contemporary Arts), Katharine Viner (Guardian deputy editor) and Stuart Broom (representing the views of the five Waterstone's reading groups).
Alexandra Harris was born in Sussex in 1981 and was educated at the University of Oxford and the Courtauld Institute, London. She is the editor (with Lara Feigel) of Modernism on Sea and is currently Lecturer in English at the University of Liverpool.
The other four books on the shortlist were:
Boxer, Beetle, by Ned Beauman (Sceptre)
Your Presence is Requested at Suvanto, by Maile Chapman (Jonathan Cape)
Black Mamba Boy, by Nadifa Mohamed (HarperCollins)
Being Wrong: Adventures in the Margin of Error, by Kathryn Schulz (Portobello Books)
