It is very difficult for a scientist to know about fields outside his specialized area of work. Nevertheless, there are a lot of books and magazines that popularize Science to make it accessible to men without a minimal scientific background. What do you think on the value of this popularization? On one hand, it would be useful to show a general view on the essentials knowledges of our age. Everyone would have the right of this basic knowledge. Furthermore, these lectures could induce to young men to initiate a scientific career. On the other hand, an "excessive" popularization can give a false idea of the objectives, methods and results of Science, with social consequences. For example, it is easy to admire technical advances Medicine. It is more difficult to appreciate changes in Physics or Paleontology. And budgets for investigation can be seriously influenced by these "popular" images. Wo would be the optimum?