Bourgeois, now 88, is a living link with the heroic period of pre-war modernism, and has retained all of that fertile epoch's ability to shock. Lars Nittve, director of the Tate Modern, is touchingly proud of her achievement here - particularly the way she has responded to a commission in a unique volume that this now reclusive artist has never, and will never, see. Instead the Paris-born, American-nurtured sculptor relies on photographs, and on trusted assistants to be her eyes and ears. "What I'm really impressed by is how she has managed to handle this space and handle this scale," Nittve says as we tour this factory of art. "For example the scale of this spider - as you come in it's always visible, but it's not so big as to overpower you from other parts of the gallery. She's worked it all out in a space that no other artist has worked in before. She's the first."

Nittve, previously director of the pioneering Louisiana modern art museum outside Copenhagen, is cheerful - almost gleeful - about the new thematic arrangment of the Tate's modern collection in the new building, which juxtaposes works from different eras and styles in an attempt to reveal common aims. With his ruddy face, ready smile and shock of sometimes unruly hair, he gives the inescapable impression, as we march round the 88 galleries at a cracking pace, of a small boy let loose in a sweet shop. A bit of a change from the sometimes funereal demeanour of his boss Sir Nicholas Serota, overall director of the Tate federation of galleries in London, Liverpool and St. Ives.