I've always found historical series to be curious in a way. A series suggests a degree of homogenization: a number of books grouped together by a common theme or goal. In the case of the Penguin History of Europe series, the goal to to provide an overview of Western/European history from ancient times through the twentieth century. Most of the volumes have been published and for the most part they're excellent surveys of their eras and likely to remain the standard works on their periods for the next generation. Yet the volumes are not uniform, and the closer they come to present times the more narrow the period being covered, with the ancient world covered in a single volume, the thousand-year span of the Middle Ages in three, and the 167 years between 1648 and 1815 covered in just one volume.
Because of this, it is not surprising that Ian Kershaw was given an entire volume to cover the 20th century. What is interesting, though, is that at some point he concluded that to do the job properly it would require two volumes, and that Penguin assented. Thus, this is simply the first half of Kershaw's overview of the century passed, providing a level of detail unprecedented in the series. That it doesn't feel bloated or dragged out is in part due to Kershaw's ability to analyze the events of this 35-year span in a way that never exhausts the reader's attention. Clearly his many years of award-winning scholarship in the era are a factor here, as he brings all of the insights he gained over the course of his career to bear in explaining the broader developments of this period.
Yet Kershaw's background also defines some of his limitations: his opening chapters on the First World War are the weakest in the book, reflecting little of the fascinating insights provided recently by such authors as Christopher Clark and Adam Tooze -- this despite the fact that their recent books are both listed in the bibliography. Once Kershaw moves into the interwar period, however, his narrative begins to shine. His focus is primarily on the political and economic developments of the time, seeking to explain (as the title indicates) how Europe descended into the hell of war and chaos and then clawed their way back. Yet he does not ignore the social and cultural changes that took place during this period, and his coverage of these areas give the reader the well-rounded narrative that such a series requires. It ends on what amounts to cliffhanger, as readers will have to wait until the succeeding volume to discover whether Kershaw can maintain the high standards he has set with this volume when explaining the developments that followed.