All Clear (and Blackout) are an excellent way to learn more about World War II/The Blitz in England. It is, however, an extremely frustrating book on many other levels.Of particular concern to me was the tendency for the historians to explain details that the other historians should hand in their degrees for not knowing. It was one thing in Book 1 to have to explain that Agatha Christie was a novelist. It's another thing altogether to revolve a major plot point on the fact that one of the historians is not able to remember the name of the 'airfield' another historian has been assigned to, and for chapters to be taken up in the quest for the airfield.The name of the place?Bletchley Park.The historians then explain to that historian that Bletchley Park is not, in fact, an airfield, but instead, the location of the most important and critical achievement in the entire war. To a historian.That incident killed the book for me, but the repetitive nature of the plot made a lot of this a slogging read. The characters are always stuck in a loop of trying to get somewhere and having a series of minor obstacles get in the way, and while this is in itself a plot point, it's not a fun one to read. All the people they meet seem like vivid and living characters, but the historians are forever brushing them off or trying to avoid them or dealing with them as another obstacle getting in the way of whatever minor task they're involved in.I did enjoy many aspects, and enjoyed the last quarter of the volume - but it took way too long to get there.