The authors are much indebted to many friends and collaborators whose con tributions to automata and language theory approach to DNA computing can be recognized in the present book. The bibliography specifies their names and we shall not repeat them here. Some of them have also read previous versions of various chapters, suggesting modifications which have improved the readability of the text. Many thanks are due in this respect to Tom Head, Hendrik Jan Hoogeboom, Vincenzo Manca, Alexandru Mateescu, Victor Mi trana, Andrei Paun, and Nike van Vugt. In particular, we are grateful to our...