Speech quality plays key role in defining the consumer's perception of the overall Quality of Service offered to him by his telecommunications service provider. For this reason, it is essential for service providers to have the ability of online assessment of the perceived quality of speech during live calls. New technologies constantly emerge in the world of telecommunications, and along with their benefits come new types of potential degradations to call quality, which need to be monitored for, discovered, and quantified in a perceptually meaningful way. This book presents a new, non-intrusive speech quality assessment model. Detection of no specific type of degradation is performed by the model, only the overall pleasantness and intelligibility is assessed. This design choice was made in order to create a quality assessment method that can capably assess the quality of speech, under never-before-seen degradation types. Performance of the proposed model is shown to be competitive with those of current state-of-the-art quality assessment models. This book should be useful to any researcher in the field of speech, as well as professionals in the telecommunications industry.