Have you recently lost a hydrogen bomb or a nuclear submarine and are wondering what a reasonable search strategy might look like? Is the arithmetic mean a good technique for making a statement about the income of a pirate crew, along with their captain? Has one of your rockets crashed because you were calculating in too small a residue class ring? Is a theory, as often claimed, just a theory? What is polynomial division and harmonic functions needed for in modern network technology? What do Fourier transformations have to do with hearing? This book is not a conventional mathematics book, which certainly does not mean that it avoids formulas or attempts to do so at all. Quite the opposite, as becomes evident even when just flipping through the pages. Nevertheless, it differs from the majority of other mathematics books in this regard.