This book has been expanded somewhat to re?ect the advances in methodologies, theory, and analysis that have transpired in the last 15 years. The chapters are now divided into numbered sections. This may be of assistance to educators who may wish to assign only certain critical sections to beginning students. Much of the organization of key chapters has been done with this in mind and in some of the opening sections; instructors will ?nd suggestions about which sections are key for fundamental understanding of that topic or method. In many chapters we have gone out on a limb and speci?ed a “recommended procedure.” In cases where there are multiple options for procedure or analysis, we usually chose a simple solution over one that is more complex. Because we are educators, this seemed the appropriate path.