Every month, thousands of stocks trade with wildly different characteristics: one is a tiny penny stock, another a trillion‑dollar giant; one has barely moved in a year, another has doubled. To make sense of the cross‑section of returns, we first need to know what a “typical” firm looks like and how much variation there really is. This chapter walks you through the central moments and percentile distributions of the most important firm characteristics, comparing what we see in the full universe of stocks with what we see after removing the very smallest or most extreme firms.