Definitions and Abbreviations. Acknowledgements. Summary. 1. Introduction. 2. Considerations on Quality. 3. Factors Influencing the Quality of Service. 4. Quality Assessment in Telecommunications. 5. Models For Predicting Speech Comm. Quality and Service-Related Models. 6. Relations between Factors Governing the Quality of Service. 7. Quality of Prediction Models. 8. Final Discussion and Conclusions. Appendices. Bibliography. Index.