The study of Earth's dynamics, from near surface earthquake displacement fields to the translational modes of the solid inner core, has long been a fascination for me. In the present work I have been influenced by Numerical Recipes, published by Cambridge University Press, to include computer code so often omitted in scientific publications. I have gone one step further to include, on the website www.cambridge.org/smylie, open source downloadable software through the Oracle Virtual Machine, allowing a full Fedora Linux operating system to be installed on users’ machines along with the TRIUMF graphics system, giving full access to Fortran, LaTeX and TeX as well as codes from the book itself and possible updates.

Throughout the writing of this book I have been very ably assisted by Dr Gary Henderson in every aspect. While I take full responsibility for any remaining errors, his high skills in English, theory and Fortran have been very much appreciated. I have been fortunate to have benefited from many teachers and professors in my studies. Reg Daniels kindled my interest in mathematics in high school, Fraser Grant introduced me to mathematical geophysics, while Tuzo Wilson hosted the geophysics laboratory at 49 St. George St. in the University of Toronto.