Ian Stewart and Jack Cohen
Scientists of the Discworld and the Roundworld, both Ian Stewart and Jack Cohen are active as researchers at the University of Warwick. Ian Stewart is a professor of mathematics and is an expert in chaos theory. Jack Cohen is an honorary professor also of the department of mathematics and his specialty is reproductive biology.
Jack and Ian's fruitful collaboration began when they met in 1990 and discovered they had many interests in common. As a result, they wrote their first popular science book The Collapse of Chaos in 1994. Figments of Reality promptly followed the year after.
By this time, Terry Pratchett had read the drafts for both books (Jack had introduced Ian and Terry at a science fiction convention in 1990) and suggestions for each other's books were flying back and forth. So it was only a matter of time before the three teamed up together.
They decided to write a new type of popular science book with alternating chapters of fiction and fact: Terry wrote a novelette about the wizards of the Discworld which Jack and Ian used as a basis for demonstrating how our own round world works. Thus the bestselling The Science of Discworld was born. A second book The Science of Discworld II: The Globe was published in 2002 and the third The Science of Discworld III: Darwin's Watch in 2005.
Cohen and Stewart's most recent pop science book was Evolving the Alien in 2002. Ian Stewart has, over the years, also written a number of SF stories and books, some (yes, again) with Jack Cohen. Heaven, the sequel to their First Contact novel Wheelers, came out in 2004.
As if their work together and with other people wasn't enough, they also have a number of individual projects such as Ian's latest solo book, Why Beauty is Truth: the Study of Symmetry. Jack, meanwhile, works as a consultant for authors and TV shows to help them come up with credible aliens (e.g., just say "no" to bumpy foreheads).
They'll be giving their popular talks on science at the Convention and hopefully Professor Cohen will finally explain why you should never have jam jars around while owls can still fall down a chimney.