In 20 years, tremendous progress has been made in Lattice Theory.
Nevertheless, the change is in the superstructure not in the foundation.
Accordingly, I decided to leave the book unchanged and add appendices to
record the change. In the first appendix: Retrospective, I briefly
review developments from the point of view of this book, specifically,
the major results of the last 20 years and solutions of the problems
proposed in this book. It is remarkable how many difficult problems have
been solved! I was lucky in getting an exceptional group of people to
write the other appendices: Brian A. Davey and Hilary A. Priestley on
distributive lattices and duality, Friedrich Wehrung on continuous
geometries, Marcus Greferath and Stefan E. Schmidt on projective lattice
geometries, Peter Jipsen and Henry Rose on varieties, Ralph Freese on
free lattices, Bernhard Ganter and Rudolf Wille on formal concept
analysis; Thomas Schmidt collaborated with me on congruence lattices.
Many of these same people are responsible for the definitive books on
the same subjects. I changed very little in the book proper. The
diagrams have been redrawn and the book was typeset in 1EX. To bring the
notation up-to-date, I substituted ConL for C(L), IdL for I(L), and so
on. Almost 200 mathematicians helped me with this project, from
correcting typos to writing long essays on the topics that should go
into Retrospective. The last section of Retrospective lists the major
contributors. My deeply felt thanks to all of them.
