Whither Quantum Computing?

A working quantum computer would be revolutionary because certain problems, such as simulating quantum materials or factorization, are easily solved on a quantum computer and probably forever hard on non-quantum computers no matter how small or how fast. Quantum computing technology is at an early stage so we do not yet know which medium is best. I discuss the principles of quantum computing, technological efforts for its realization, and applications for when a quantum computer eventually works.