A small paperback version of Masquerade has come out in England, which
contains a history, who solved it, and what the solution is. I don't know
if it is available in the U.S. yet, but I have seen a copy, and got the
following info: The full title & subtitle is "The Treasure Hunt of the
Century / Masquerade / Kit Williams Tells the Answer to the Riddle",
ISBN 0 224 02937 1; Jonathan Cape (pub), Thirty Bedford Square, London.
I will check around to see if it is available --- Just did; At lease
one local book store (Printers Inc, in Palo Alto, Ca.) says it's on order,
and they expect in in a day or two.
If anyone wants a rough idea of how to find the solution, I can put it
on the net.