MJD sincerely acknowledges several previous doctoral students: CLF Ma, Serguei An, Yegao Xiao, Yasser El-batawy, Yasaman Ardershirpour, Naser Faramarzpour and Munir Eldesouki, as well as Dr. Ognian Marinov, for their generous assistance and support. He is also thankful to his wife Meena as well as their sons, Arif, Imran and Tariq, for their love, support and understanding over the years.
SK would like to thank his former and current research students, P. Zhang, D. Yang, M. Malekiha, S.N. Shahi and J. Shao, for reading various chapters and assisting with the manuscript. He would also like to thank Professor M. Karlsson and Dr. S. Burtsev for making helpful suggestions on several chapters. Finally, he owes a debt of gratitude to his wife Geetha as well as their children Samarth, Soujanya and Shashank for their love, patience and understanding.