This cross-disciplinary field utilizes the strange effects of quantum mechanics to enable information processing and computing that would be impossible on traditional 'classical' computers. The field has developed rapidly over the last few years due in part to its tremendous technological potential. The theoretical foundations of the subject are clearly established and good textbooks are available. However, many experimental directions are under investigation and hardly any book describing them is available on the market. Quantum cryptography, for example, has already evolved to marketable devices. Most of the books on quantum information and/or quantum computing address the important aspect of optical implementation only briefly. This book solves that by focusing on all light-based approaches to quantum computing.