The surface electrons of 3D topological insulators are known to possess a helical Dirac spin texture [1] that can be exploited for studying exotic quantum states (such as condensed matter versions of Majorana fermions, axions and supersymmetry) to pragmatic spintronic devices for information technology. I will provide a perspective on this field, with examples of how we create novel phases of matter by interfacing a topological insulator with magnetism [2] and superconductivity [3]. I will also discuss the recent emergence of "topological spintronics," demonstrating how the spin texture of a topological insulator leads to striking phenomena useful for devices, such as the generation of a spin-orbit torque of record efficiency at room temperature [4] .