Chapter headings. Series preface. Preface and acknowled gements. Principal symbols. List of tables. Introduction. Some basic con cepts and definitions. Measurement: omnidirectional. Directional measure ment (in situ sensors). Analysis and interpretation: omnidirectional. Es timating extreme wave height. Analysis and interpretation: directional d ata. Remote sensing of waves. Waves in finite depth. Wave generation by wind, and wave forecasting. Nonlinear effects. Errors and uncertainties. Appendix 1 The computation of wave spectra. Appendix 2 The spectrum o f the product of two random variables and that of the square of one rand om variable. Appendix 3 Cross-power Spectra. Appendix 4 Digital integr ation and filtering. Appendix 5 Some useful statistical formulae. Appen dix 6 Fitting regression lines to wave data. Appendix 7 Initial analys is and on-line recording of wave data: practical recommendations. Refere nces. Subject index.