The book appeared first in 1979, published by Teubner Verlag. The book is now out of print, but their are still many people who refer to it, especially to the first chapters devoted to rational transductions. Therefore I make the first four chapters available in electronic form. I am grateful to persons who indicate me mistakes I did in typing the text.
The bibliography is of course inaccurate now, and there are many new and important results that have been found since the late seventies. The latest modern exposition is presently the book of Jacques Sakarovitch "Elements of Language Theory", available in French and that appeared recently in English at Cambridge University Press.
There is one mysterious item that can be answered now: I give a reference to a forthcoming volume C of Eilenberg's book. At that time, Samuel Eilenberg indeed planned to write a four volume book, the third volume devoted to context-free languages and the forth to decidability. However, he did not finish this third volume.
There exists a numeric version of the book, download here.
Last modified Oct 13, 2012.