Author(s): Patryk Lipka-Bartosik, Henrik Wilming, and Nelly H. Y. Ng A branch of quantum information is concerned with transformations that are possible given certain resources: for example, quantum teleportation moves a quantum state from one place to another, aided by entanglement and classical communication. Certain other tasks are provably impossible. But, as surveyed in this review, a surprising fact is that some tasks become possible if another quantum state is present, even if this state is returned untouched at the end of the task. This “quantum catalysis” enables a large variety of interesting tasks, with applications ranging from cryptography to thermodynamics. [Rev. Mod. Phys. 96, 025005] Published Thu Jun 27, 2024