ENTANGLEMENT. REALITY. Books containing these three words are typically fluff or incomprehensible; this one is not. "Q is for Quantum" teaches a theory at the forefront of modern physics to an audience presumed to already know only basic arithmetic. Topics covered range from the practical (new technologies we can expect soon) to the foundational (old ideas that attempt to make sense of the theory). The theory is built up precisely and quantitatively. Deceptively vague jargon and analogies are avoided, and mysterious features of the theory are made explicit and not skirted. The tenacious reader will emerge with a better technical understanding of why we are troubled by this theory than that possessed by many professional physicists.