A few years ago, when I embarked upon, what seemed at the time an unending, impossible journey into the dark unknown, my main sources of inspiration were two people who believed that I could do it-my major professors Dr. Thomas Rudolphi and Dr. Frank Rizzo. It is to these two gentlemen that I owe my deepest gratitude. They have been a constant source of encouragement, learning, guidance, and help. I am also indebted to Dr. Ron Roberts for his invaluable suggestions and help. My special thanks go to Dr. Paul Martin (University of Manchester, UK) who brought to my attention the unique way of describing the scattered field, a key component of this work.