Fascinating in all sorts of ways, of course, but one aspect of this book that's stayed with me is Sereny's exploration of that grey area between knowing and not knowing. The main question asked is: how much did Speer really know about Nazi atrocities - and how much would he admit he knew? Sereny pursues those questions doggedly, with one eye on the hard reality and another on Speer's willful refusal to face up to that reality.

Only once in the whole book (if I remember rightly) does she expand the implications of the example of Speer to include all of us: recognising that to some extent we all inhabit that grey area much of the time, choosing what knowledge we will allow to shape our view of the world, and which things we will let slip off our minds like water. But by the time I'd finished the book, my understanding of humans' ability to lie to ourselves and each other was vastly enriched.

An extraordinary book.