Why will your neighbor downstairs live longer than you? What color is the mirror? How much does Thor's hammer weigh? Why can't we travel back in time? How many megapixels does the human eye have? To read this book, you will dedicate 0.0005% of your life, from 7,200 to 14,400 seconds.

Perhaps as much as for Blade Runner 2049 or for the original Star Wars trilogy. But did you know that time is something relative, like so many other things? If a long and happy life awaits you, you will live for over two billion seconds, although you will spend one third of that sleeping. The remaining seconds, after quite a while on the pillow, you will be awake, you will live them, you will enjoy them. Because they can be wonderful.

So think about how you will make the best use of them. In a few years, some of the things you read in this book, many of which are considered certain today, might not make any sense. Nothing stays the same, nothing is stable. "The only constant is change," predicted Heraclitus 2,500 years ago. It is the wonder of science that moves relentlessly forward day by day.

That’s why I want this book to be a source of inspiration for you, to help you seek your own answers to all the questions that concern you, and to search for those answers without resorting to standardized knowledge or pseudoscientific myths.

A BOOK FOR YOUNG MEN AND WOMEN, FOR THEIR TEACHERS AND EDUCATORS, AND FOR ANXIOUS MINDS REGARDLESS OF AGE.