Sonar performance modelling (SPM) is concerned with the prediction of quantitative measures of sonar performance, such as probability of detection. It is a multi-disciplinary subject, requiring knowledge and expertise in the disparate fields of underwater acoustics, acoustical oceanography, sonar signal processing and statistical detection theory. No books have been published on this subject, however, since the 3^rd edition of Urick’s classic work 25 years ago and so Dr Ainslie’s book will fill a much-needed gap in the market. Currently, up-to-date information can only be found, in different forms and often with conflicting information, in various journals, conference and textbook publications.