Security, technology and public life sit in separate sections on most bookshelves and remain inseparable in practice. Counter-Intelligence is filed across all of them here, alongside memoir and business, which is a fair map of the ground Robert Hannigan covers.
Work that lands in that many sections tends to be arguing across boundaries rather than within one, and it asks a little more of a listener than a single-subject read. The reward is a wider view: the technical, the political and the human treated as parts of the same problem.
An average of 4.3 across a decent spread of reviews suggests a book that has found its readers without setting out to flatter everybody.