Single Digits is not a cultural survey of the small numbers it sings the praises of. One is the Loneliest Number, two’s company, three’s a crowd, Seven Brides for Seven Brothers, Eight is Enough – these you will not find here.
Instead, as the preface explains: “Some of the topics, such as the Pizza Theorem, require little mathematical background and are understandable by a curious 12-year-old; other sections require modest amounts of technical math, while a few sections, such as the section on E8, allude to such sufficiently advanced material that it should not be read with small children present.”
This is a volume of math for math's sake. If you can appreciate seemingly magical or coincidental results from what might as well be thin air, then this is your book. And the mathematics itself is not too complex – but the equations are not for novices (as the preface notes). You will have to work some to follow along, or just skip the proofs and enjoy the wizardry – or stand in the center of a four-way intersection, roll a tetrahedral die, and walk north for 1, east for 2, south for 3, or west for 4. Then repeat. And repeat. And repeat. Sooner or later you will return to your original spot. But not necessarily so for three dimensions instead of two. Fun stuff!