Includes images of captured encoded dispatches and examples of keys used to crack them.

Used in Acceptable condition. 2008 Paperback edition. Spine is creased in the middle. Spine corners are lightly bumped. Crease to bottom edge of spine. The other corners are lightly bumped. Fingermark staining in the middle of the page block. Internally clean and tight copy. Small dents to rear cover. Foxing to top edge of the page block. Shelf wear to covers. Not an ex-library book. Please see the pictures for closer detail.