A lot hinges on mathematical modelling these days — lockdowns and climate change being two extreme examples — yet Dr No suspects, based on a recent chat with an arts degree educated contemporary friend of his, that those without a scientific background are not always entirely sure what modelling is (Dr No uses modelling in this post to mean mathematical modelling, not modelling Airfix battleships or balsawood planes), and so end up either being led by the science, like a bull led by the ring in his nose, however preposterous the so-called science, or alternatively end up decrying the whole bally lot as humbug, and no better than lies, damned lies and statistics. This post is an attempt to make modelling clearer — what it is, and is not — to those without a science background, and to provide a sound reason why we should all treat predictive modelling with extreme caution.