Several of the contributions to this volume bring forward many mutually
beneficial interactions and connections between the three domains of the
title. Developing them was the main purpose of the NATO ASI summerschool
held in Montreal in 2003. Although some connections, for example between
semigroups and automata, were known for a long time, developing them and
surveying them in one volume is novel and hopefully stimulating for the
future. Another aspect is the emphasis on the structural theory of
automata that studies ways to contstruct big automata from small ones.
The volume also has contributions on top current research or surveys in
the three domains. One contribution even links clones of universal
algebra with the computational complexity of computer science. Three
contributions introduce the reader to research in the former East block.