This book provides the reader with a clear overview of the considerable body of research and development work carried out in the last five years on microstructured polymer optical fibres (mPOFs) and the huge potential that they offer in a diversity of application areas. It contains sections explaining the guiding mechanism in these fibres, the fabrication methods, the variety of fibres that can be made, the optical properties that can be achieved and an outline of potential applications. It also explains the state-of-play with respect to current research and issues that have still to be resolved. It includes for the first time details about the fabrication process for these fibres. This description is extended to apply to other classes of microstructured fibres including those made from silica. The book provides an excellent introduction to this new technology, making it accessible to industry, technical and research audiences.