Copyright protects far less than most people think and lasts far longer than most people expect. This article explains what it actually covers — original expression fixed in a tangible medium — and the enormous categories it does not: ideas, facts, systems, procedures, titles, names, and useful articles. It explains the two rules that decide almost every practical dispute: that the author is whoever created the work unless a narrow statutory exception applies, and that registration before infringement is what unlocks statutory damages and attorney's fees. It walks through fair use as courts actually apply it, including the recent tightening of what counts as transformative. It covers licensing, the difference an exclusive license makes, the DMCA notice-and-takedown system that governs most online disputes, and the termination right that lets authors reclaim rights decades later. It closes with what to do when your work is copied, and what to do when someone says yours infringes.