There are some dicey moments in the second of Stieg Larsson 's ' Millennium Trilogy ' crime thrillers. The one that really got me was when his arguably- too -brilliant social-misfit-hacker protagonist Lisbeth Salander finally (after several weeks of intermittent, amateur endeavour) solves the riddle of Fermat's Last Theorem -- a conjecture which famously remained unproven for 358 years after the tantalising claim by the eponymous theorist , scrawled in the white space of his copy of the ancient Greek mathematical text Arithmetica , that he knew a proof but that it was too large to fit in the margin. Salander began her advance towards the house, moving in a circle through the woods. She had gone about a hundred and fifty metres when suddenly she stopped in mid-stride. In the margin of his copy of Arithmetica, Pierre de Fermat had jotted the words I have a truly marvellous demonstration of this proposition which this margin is too narrow to contain. The