Foundations

Four pillars live in this domain, and between them they hold up everything else in Data Science & AI: statistics for describing data honestly and doubting what you see, the mathematics models are made of, what the machine actually does with your code, and the Python craft to express all of it cleanly. Nothing here is a detour — when a later chapter feels like magic, the missing piece is almost always in one of these four rooms.

You do not need them all at once, and you do not need them in order. Each pillar opens from zero and can be entered on its own; a perfectly good path is to dip back in whenever a later block sends you here for a missing idea. The stack below shows why the domain matters: everything above it stands on it.