Eternity lasts a long time, especially towards the end. Even the longest journey begins with the first step! And what does the first step begin with? With the first ten centimeters! And what do those begin with? With the first five centimeters. And because this continues endlessly, one might not even start to move. Diogenes' answer to this paradox of Zeno was simple: he stood up and walked around his barrel once. Infinity eludes our everyday imagination, yet we deal with it as if it were completely natural. Those who hope for it call it heaven or eternal life. In mathematics, things often go towards infinity, while physicists speak of singularity or black holes. The risk of infinity is the onset of boredom, as everything just keeps going on. This will not happen to you with this book: it is finite, after all.