Chris Calladine is Professor of Structural Mechanics at the University of Cambridge. In addition to researching aspects of structural engineering, he has applied the methods of structural mechanics to the study of flagella and DNA.Horace Drew solved several of the first DNA crystal X-ray structures with Richard Dickerson at Caltech, and subsequently spent five years researching DNA and chromosome structures with Aaron Klug at the MRC Laboratory of Molecular Biology in Cambridge, UK He now lives in Australia and is a Principle Research Scientist at the CSIRO Division of Biomolecular Engineering in Sydney.Ben Luisi works in the Department of Biochemistry at the University of Cambridge, where he has an appointment as professor of structural biology. He and his colleagues study the structure and mechanism of efflux pumps and the riboregulatory machinery that help to control the expression of the pumps and other complex systems in bacteria.