Lambda the Ultimate

"Algebraic Structure Theory of Sequential Machines" will seem hopelessly out of date to some people, but the contemporary interest in concurrency gives the book a new found importance. I have a complete searchable scan of the book that I would post online if I knew how to get permission from Prentice-Hall. Does anyone have any ideas?

Here is the very interesting preface of the book.

The explosive development of information-processing technology during
the last two decades has stimulated the vigorous growth of an Information
Science. This new science is primarily concerned with the study of information
and the laws which govern its processing and transmission. A very
active part of this science is the study of sequential machines or finite automata
which are abstract models of digital computers. The aim of this research
is to provide a basic theoretical background for the study of digital computers
and to contribute to a deeper understanding of discrete or finite
information-processing devices. This area of research was started around
1954 by D. A. Huffman and E. F. Moore and has since undergone a considerable
growth in several diverse directions. In the period from 1960 to
1965, a body of results we call "structure theory" was created and developed
to a considerable degree of completeness and unity. This book is an exposition
on the foundations, techniques, and applications of this theory.

By a structure theory for sequential machines, we mean an organized
body of techniques and results which deal with the problems of how sequential
machines can be realized from sets of smaller component machines, how
these component machines have to be interconnected, and how "information"
flows in and between these machines when they operate. The importance of
machine structure theory lies in the fact that it provides a direct link between
algebraic relationships and physical realizations of machines. Many structure
results describe the organization of physical devices (or component machines)
from which a given machine can be synthesized. Stated differently, the
structure theory describes the patterns of possible realizations of a machine
from smaller units. It should be stressed, however, that although many
structure theory results describe possible physical realizations of machines,
the theory itself is independent of the particular physical components or
technology used in the realization. More specifically, this theory is concerned
with logical or functional dependence in machines and studies the information
flow of the machine independently of how the information is represented
and how the logical functions are to be implemented.

The mathematical foundations of this structure theory rest on an algebraization
of the concept of "information" in a machine and supply the algebraic
formalism necessary to study problems about the flow of this information
in machines as they operate. The formal techniques and results are
very closely related to modern algebra. Many of its results show considerable
similarity with results in universal algebra, and some can be directly derived
from such considerations. Nevertheless, the engineering motivation demands
that this theory go its own way and raises many problems which require
new mathematical techniques to be invented that have no counterpart in
the development of algebra. Thus, this theory has a characteristic flavor and
mathematical identity of its own. It has, we believe, an abstract beauty
combined with the challenge and excitement of physical interpretation and
application. It falls squarely in the interdisciplinary area of applied algebra
which is becoming a part of engineering mathematics.

This book is intended for people interested in information science
who have either an engineering or mathematical background. It can be read
by anyone who has either some mathematical maturity, achieved through
formal study, or engineering intuition developed through work in switching
theory or experience in practical computer design.

Enough concepts of machine theory and machine design are introduced
in the first chapter so that a mathematician may read the book without any
experience with computers or switching theory. A preliminary chapter on
basic algebraic concepts supplies enough mathematics to make the book
self-contained for a non-mathematician. A good number of examples are
given to supply the engineer with an interpretation or application of the
mathematics.
J. HARTMANIS
R. E. STEARNS