Marcel Escudier is Emeritus Harrison Professor of Mechanical Engineering at the University of Liverpool. He has written many journal articles and two books, The Essence of Engineering Fluid Mechanics (Prentice Hall, 1998) and Introduction to Engineering Fluid Mechanics (OUP, 2017). He is a Fellow of the Royal Academy of Engineering, a Fellow of the Institution of Mechanical Engineers, and a Fellow of the City and Guilds of London Institute.Tony Atkins was Emeritus Professor of Mechanical Engineering at the University of Reading and Visiting Professor at Imperial College. He authored over 150 journal articles and several books, including The Science & Engineering of Cutting (Elsevier, 2009). He was a Fellow of the Royal Academy of Engineering, a Fellow of the Institution of Mechanical Engineers and a Fellow of the Institute of Materials, Minerals and Mining. Less