It's true that they've now, they’re… when we studied them, there were… had a kind of interest from the point of view of giving low energy approximation to colliding monopoles, which is of... of interest in some aspects. And we get a nice mathematical story, and then that's sort of finished off and now they've reappeared in more sophisticated form in connection with these new ideas about duality, in theory. And... and, well I think that the… these monopole spaces form mathematically a nice class of manifolds, a nice class of metrics which obviously has lots of nice features. It fits into all sorts of stories, and I think they probably, you know, will have a kind of permanent home as something on the shelves that... that you can pull down and use in different contexts.

But whether you think of them as mathematical objects or as physical objects, I think this kind of slightly artificial distinction, you know, doesn't make much sense after a while. So one shouldn't be surprised if they recur. They have a, kind of, a rather natural fundamental role in the physics and they have, once you've understood them well, a rather natural mathematical interpretation as a class of manifolds of a certain type, which has interest of its own kind. So I think they're... they’re now well established animals, or books, whatever you like to call them – mixing my metaphors – which are of permanent value, yes.