"...this is a beautifully crafted book, which can be read at several levels. The beginner can concentrate on principles, study the algorithms and the numerical examples, and then begin to use the Common USP code obtainable through electronic-mail. The experienced reader can proceed to study the more advanced material that the authors have isolated in 'Comments and Extensions' to appropriate sections presenting more general material. This presentation style works very well indeed, because it has enabled the authors to produce a volume that is both elementary and advanced....This is an outstanding volume, one that ought to be on the bookshelves of students as well as those of experienced practitioners of this arcane art." Sven Treitel, American Scientist