Practical quantum computing still seems more than a decade away, and researchers have not even identified what the best physical implementation of a quantum bit will be. There is a real need in the scientific literature for a dialogue on the topic of lessons learned and looming roadblocks. This reprint fromQuantum Information Processing is dedicated to the experimental aspects of quantum computing and includes articles that 1) highlight the lessons learned over the last 10 years, and 2) outline the challenges over the next 10 years. The special issue includes a series of invited articles that discuss the most promising physical implementations of quantum computing. The invited articles were to draw grand conclusions about the past and speculate about the future, not just report results from the present.

Invited Articles.- Progress in Quantum Algorithms.- NMR Quantum Information Processing.- Quantum Computing with Trapped Ion Hyperfine Qubits.- Ion Trap Quantum Computing with Ca+ Ions.- Quantum Information Processing in Cavity-QED.- Quantum Information Processing with Trapped Neutral Atoms.- The Road to a Silicon Quantum Computer.- Controlling Spin Qubits in Quantum Dots.- Spin-based Quantum Dot Quantum Computing in Silicon.- Optically Driven Quantum Computing Devices Based on Semiconductor Quantum Dots.- Implementing Qubits with Superconducting Integrated Circuits.- Towards Scalable Linear-Optical Quantum Computers.- Photonic Technologies for Quantum Information Processing.- Contributed Articles.- Quantum Computer Development with Single Ion Implantation.- Bang-Bang Refocusing of a Qubit Exposed to Telegraph Noise.- Quantum Computing and Information Extraction for Dynamical Quantum Systems.- One-Dimensional Continuous-Time Quantum Walks.