"It's like walking into a giant pop-up book", was the verdict of Quentin Blake, the illustrator of Charlie and the Chocolate Factory, The BFG and a host of other Dahl stories. The newly opened gallery is not just a themed fun palace - it is an interactive children's museum. It ingeniously links Dahl's stories to objects on display and teaches children about the world around them in an entertaining and stimulating way.
The Great Glass Elevator from Charlie and the Chocolate Factory dominates the entrance to the atrium of the gallery. The voice of Willy Wonka, the great sweet inventor, chivvies you inside his far-from-ordinary lift. The domed roof of the atrium is dotted with planets from outer space, as seen from the Glass Elevator, and Charlie and Mr Wonka are there among them. Enormous, delectable Wonka sweets decorate the huge windows above the gallery entrance. Huge, brightly coloured "dream bottles" from the story of the Big Friendly Giant sit on a high shelf.
Dangling from the ceiling in the atrium is the oddest chandelier, suspended from which are a hotchpotch of objects including a policeman's helmet, a tin of Spam and a truncheon. A verbal joke made visual. "What does a policeman have in his sandwiches? Truncheonmeat." Children are encouraged to look at things carefully and to think about words and their meanings - and jokes. Roald Dahl loved jokes.
Inside the Giant Peach, re-created in the Discovery Gallery, are drawers with enticing labels. "Seacumbers and sandthumpers" reveals a selection of shells and coral, and the cheeky title "Even older than Grandma" introduces a drawer full of fossils.
Across the room, Fantastic Mr Fox's tunnel just begs to be crawled through. Glass covers in the floor reveal underground treasures - some broken bits of pottery and more fossils. Through peep-holes in the walls a stuffed mole and badger take on lifelike qualities in their own small burrows.
Above the tunnel are huge, transparent pipes filled with luminous green bubbles which transport you back to the Chocolate Factory and the world of amazing Wonka creations.
Next door is Matilda's Library, a quieter area in which to look at the array of Dahl's books or pick up an earpiece to listen to one of the stories. A video and photographic display tell us more about his life and work at Great Missenden, down the road from Aylesbury.
Ascending the brightly coloured metal stairway to the upper floor, you enter the Imagination Gallery. On the door is a copy of the steel hip that Roald used as the handle to a filing cabinet drawer in his study. (This was his original false hip, which he had had replaced). In this room, illusion and reality intermingle. There are distorting mirrors and different contraptions which introduce the world of animation, including the Victorian magic lantern. You can create your own animated story sheet at the work benches provided.
The Twits' Upside Down room, suspended from the gallery roof, relates to all the experiments with illusion and reality. When the Twits found their room like this, they didn't know whether it was the room that was upside down, or themselves. Animated visuals on a computer screen explain how the eye sees things the wrong way up, which are then corrected by the brain. The refrain on this dip-in-dip-out programme is "Baffle your brains and boggle your eyes - Things are not always what they seem." The images back this up by showing how one thing can soon turn into something else. It is true Dahlesque philosophy.
The gallery, originally an 18th-century coach house, is the creation of the museum designers Morag Bremner and Mick Orr, who have also redesigned the adjacent Buckinghamshire Museum - recently the winner of the Museum of the Year award. They have worked together with the Buckinghamshire Museum team and with Liccy Dahl. "We had crazy afternoons coming up with ideas," says David Orr. "The problem has been deciding which ones to use." The funding of more than pounds 600,000 came from the Heritage Lottery Fund, the County Council, Liccy Dahl and private gifts.
The Roald Dahl Children's Gallery inspires inquisitiveness as well as fantasy and imagination. "Watch with glittering eyes the whole world around," said Dahl in The Minpins, "because the greatest secrets are always hidden in the most unlikely places."
The Roald Dahl Children's Gallery, Church Street, Aylesbury, Buckinghamshire (01296 331441). Entrance fee pounds 1.50. Open 10am-5pm weekdays and Saturday; 2-5pm Sunday.