This electronic book, ``Imaging the Earth's Interior'' is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This book is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Massachusetts Ave., Cambridge, MA 02139, USA.
I reserve the right to distribute this book and its software for a profit. Paraphrasing The GNU General Public License, you may make modifications and copies and distribute them also, but your distribution which includes my work must be distributed free.
Jon Claerbout October 31, 1997