In response to Alex Perry (NCE 6 April) I can suggest a mathematician's book to take a leaf from. Ian Stewart writes as follows in his book 'Life's Other Secret - The New Mathematics of the Living World' (Penguin 1999).
'The test of true engineers is not that they can build one particular machine. It is that they understand the general principles behind machines and can apply them to whatever task they confront.'
John Read, John.Read@arup.com