xxv Acknowledgment First of all and foremost we say thank you very much to all contributors that allowed us to concretize this book. We are grateful with them for the time, efforts, abnegation, and patience they've shown dur- ing the phases of selection, revisions, and finalization of their chapters. We would like to say thank you also to the members of the book Editorial Advisory Board for their assistance in making a good result. In particular, to Dr. Walfang Gaentz for his illuminating foreword conceived for this book. The chapters included in this book have been reviewed in double-blind process, with three reviewers for each chapter. We remark the authors have addressed point by point the detailed and valuable comments of the reviewers involved in the evaluation phase. We also say thank you to members of the MDSLAB Messina, Università degli Studi di Messina, who helped us on chapters' reviews and book organization. Massimo would like to thank Carmen, his wife, who bears and supports him during his very stressing commitments, and to his sweet daughter, Gaia, who gives him beautiful smiles and carefree moments. A particular thank you is also due to Villari and Nazzari families; Massimo's relatives who always sustain him. Francesco would like to say thanks both to his kind partner in love, Miriam, and his relatives, for their patience and support provided while the book has been written. Ivona would like to thank Manda, Ivo, Igor, and Harald for their invaluable support and love. Massimo Villari Università Degli Studi di Messina, Italy Ivona Brandic Vienna University of Technology, Austria Francesco Tusa Università Degli Studi di Messina, Italy