Preface to network distribution

This book was originally published by Blackwell's in 1985. Only later in my next book in 1992, ``Earth Sounding Analysis: Processing versus Inversion'' did I understand how to make an electronic document where all the illustrations are reproducible, being recalculated from original data, parameters, and programs. I tried revising this book to bring it up to that standard, the standard of the 1992 book, however too much had been lost, indeed, many of the examples shown in this book were not done at our laboratory. When this book was declared out of print about 1992 I resolved to bring out this electronic version, almost a revision of the original and make it freely available over the internet. I have not yet learned how to make all the software conveniently downloadable from the internet. The figures in this book contain pushbuttons in the figure captions. Those 54 figure captions containing the letters [ER] point to software that is easily reproducible if you have the electronic book. Of these, 11 figures include movies. On these reproducible figures, you can dig in, change data, change parameters, or even change the theory. You then press the button in the figure caption and watch the figure rebuild itself (on UNIX based computers) to your specifications. I am particularly indebted to my colleague, Matthias Schwab, whose continuing collaboration is making possible these interactive documents on CD-ROM.