The purpose and organisation of this book are described in the preface to the first edition (1988). In preparing this edition minor changes have been made, par­ ticularly to Chap. 1 (Vol. 1) to keep it reasonably current, and to upgrade the treatment of specific techniques, particularly in Chaps. 12-14 and 16-18. How­ ever, the rest of the book (Vols. 1 and 2) has required only minor modification to clarify the presentation and to modify or replace individual problems to make them more effective. The answers to the problems are available in Solutions Manual jor Computational Techniques jor Fluid Dynamics by K. Srinivas and C. A. J. Fletcher, published by Springer-Verlag, Heidelberg, 1991. The computer programs have also been reviewed and tidied up. These are available on an IBM­ compatible floppy disc direct from the author. I would like to take this opportunity to thank the many readers for their usually generous comments about the first edition and particularly those readers who went to the trouble of drawing specific errors to my attention. In this revised edi­ tion considerable effort has been made to remove a number of minor errors that had found their way into the original. I express the hope that no errors remain but welcome communication that will help me improve future editions. In preparing this revised edition I have received considerable help from Dr. K.