THE UNKNOWABLE G J Chaitin, IBM Research Published by Springer-Verlag Singapore, 1999, x + 122 pages, hardcover, ISBN 981-4021-72-5 Order from Springer-Verlag, Amazon, Barnes & Noble Reviewed in New Scientist, Comp Rev, AMS Notices, J Sci Expl Translated in Japanese PREFACE Having published four books on this subject, why a fifth?! Because there's something new: I compare and contrast Gödel's,