How was it cracked?

The winning team consisted of Fredrik Almgren, Gunnar Andersson, Torbjorn Granlund, Lars Ivansson and Staffan Ulfberg. They began working on the Challenge soon after The Code Book was published in September 1999, when Fredrik Almgren was in London taking part in a juggling festival and happened to see a copy of the book.

They have written an excellent 40-page document that outlines their trials and tribulations. It outlines their strategy for cracking each stage of the Cipher Challenge, and it is not only informative, but also largely comprehensible. The document is available in the following formats:

HTML files
PDF files
PS files
DVI files

You can download the Adobe Acrobat Reader here.