This book evolved from a course at our university for beginning graduate stu- dents in mathematics-particularly students who intended to specialize in ap- plied mathematics. The content of the course made it attractive to other math- ematics students and to graduate students from other disciplines such as en- gineering, physics, and computer science. Since the course was designed for two semesters duration, many topics could be included and dealt with in de- tail. Chapters 1 through 6 reflect roughly the actual nature of the course, as it was taught over a number of years. The content of the...