You wait all Christmas for a Kraftwerk book and then two show up at once.
Now available on pre-order (as advised by my steady stream of Amazon recommendation emails) is Kraftwerk Publikation by David Buckley: a biography about Dusseldorf's most famous cycling enthusiasts. Then there's Continuum's Kraftwerk: Music Non-Stop which is actually a collection of essays and includes intriguing chapters like "Vorsprung durch Technik – Kraftwerk and the British Fixation with Germany". £14.96 and £12.61 respectively.
I previously read Wolfgang Flür's I Was a Robot a few years back so it's the latter that's really got my interest. And my order.
Kraftwerk: Music Non-Stop