The Roald Dahl Museum and Story Centre, Great Missenden, Buckinghamshire

'Why paint it blue?' I wondered as I approached the NEW Roald Dahl Museum and Story Centre in Great Missenden. The answer is that this blue museum building, with the BFG (Big Friendly Giant) painted more or less in his full height, is not a literary but a children's museum, created in honour of a man renowned as a very great children's author, and one who apparently did not like museums (or children) much.

The curator, designers - and the late author's family - had quite a task creating an institution to celebrate the life and work of somebody so non-institutional. The result is really very wonderful.

A more traditional literary museum might have concentrated on the objects that dominate the literary world (as happens at national libraries which collect actual books).

Or it might have presented the author's home and belongings (as is the case for the Brontës at Howarth Parsonage), or kept his/her belongings in a university collection (as in the Harry Ransom Collection at the University of Texas).

But the Roald Dahl Museum does something very contemporary in the museum world: it creates a space, a kind of multi-dimensional and multimedia environment, around the museum's central ideas and concepts about what a museum is and does, and what the author's work was about.

We are a world away from the days when a museum simply displayed objects. Here we see a museum presenting a writer's biography (illustrated with objects and other documentary evidence from his life), intermingled with his works (presented through three-dimensional structures and interactives), culminating in a gallery devoted to storytelling.

It is sometimes said that museum exhibitions 'tell stories', whether deliberately or implicitly, through the way objects have been displayed and explained to the visitor. This is certainly the case here. The Roald Dahl Museum has been carefully designed, to make sure it can do a particular kind of work.

Of course it is first and last about Roald Dahl, but it is remarkably loyal to his complex personality. Far from elevating him to the saintly status of a divinely inspired creator, it presents the naughty schoolboy that fate turned into a RAF fighter pilot during world war two, and eventually into a spokesperson for children/characters who have to survive by their wits in an often hostile world.

You enter the space devoted to his boyhood through a doorway shaped like - and smelling like - huge chocolate bars, with the word 'Boy' apparently sprayed on the wall above, to find yourself in the most conventional room in the exhibition: a bright red and purple space with images of Dahl-the-schoolboy; a mock-up of his schoolbag and of naughtily ingenious inventions for soaking passing ladies in water; and a showcase with his mother's letters sent to his school and his stamp collection.

From the first moment, there is a link between Dahl the individual boy, and Dahl the schoolchild like all other schoolchildren. This is the central theme in much of his creative work: his young heroes are both special and ordinary, they must be respected and understood in both ways.

The second gallery -Solo, as in flying solo - brings adulthood into play, through objects, film and recorded voices, in a space dominated by outsize books (which can be used as seating), a giant pencil and angle-poise lamp.

It is tempting to see this as a simple way of creating a space for adult and child, which each can fill with their responses to the multimedia show surrounding them.

But it may also acts as a kind non-age-specific space that is neither entirely comfortable to child or adult. There is stuff to do and stuff to think about. But it is also a little unsettling, a little Dahl-esque.

The culmination of the tour is the Story Centre Gallery. This is the heart of the display, where Dahl's own storytelling is celebrated in a recreation of his writing hut. You can sit in a replica of his chair, by a replica of his desk and filing-cabinet (which are, of course, interactives) and play at being the author.

This is the experience that many conventional museums about writers offer to the visitor: visit the Hans Christian Andersen Museum in Denmark or Shakespeare's birthplace in Stratford and you yourself are there, where the author once was, and you may wonder what that environment tells you about their lives, works and creativity.

But in the Roald Dahl Museum, the Story Centre encourages you to go to work as a writer yourself. You encounter not only Dahl's work (and that of his illustrator, Quentin Blake) but also the thoughts of other authors about how they create their works.

Interactives allow you to play with words, sentences and stories, you can create your own short film and put together your own narrative. This modern museum is a production unit, a place that does not just encourage contemplation but also creativity.

The museum's actual collection and its true glory is the archive, which has stayed in the UK and will, one assumes, not only preserve the author's original manuscripts for the future but also oblige researchers to visit the author's home town in order to work in the archives.

The museum has been created in and around a Grade II listed building in such a way that the galleries, offices and learning facilities and cafe surround a courtyard with cobbles and - in honour of Dahl's Norwegian ancestry - birch trees.

Visitors are enclosed by the museum building but are not always indoors: the museum creates a special world that you can slip out of when you need to.

Once inside the gallery, you find yourself having to get used not so much to the dark as to the multitude of sense impressions coming at you in the form of sound recording, film, display cases, and huge piles of books that form writing desks and seats at different levels. As with other good museums, you need to stay long enough to let the impressions work on you.

The museum aims to inspire the love of creative writing, through reading and through storytelling. I saw adults and children playing and enjoying themselves in the Story Centre: it will become a shrine to the artist and his artform.

Dahl would have liked his own museum. The kind of museum he hated would have been that old fashioned, dark, dusty and earnest institution that was once used to torture the minds of schoolchildren (and which I loved, as it happens).

This one is marvelous, colourful and magical and will become a place of pilgrimage to Dahl fans of all ages.

Hans Christian Andersen is a senior lecturer in cultural tourism at Northumbria University

Project data

Cost: £4.3m

Funders: Penguin, Random House and others (the building and archive, worth £2m, donated by the Dahl family)

Designers: Bremner and Orr

Architects: Hawkins/Brown