The depth and breadth of the author's knowledge and research make this an awesome, if at times heavy, book.
For me, its greatest asset is the way that this book takes familiar elements and weaves them into a coherent whole. The individual portraits presented in this book are detailed in themselves, but when they are portrayed as a single panorama of the twentieth century it is incredible to behold.
This detail is also the book's downside. In those sections where I had too little existing knowledge to build upon I found the prose too dense and anecdotes distracting - but that may say more for my history than the author's prose.
If you are looking for an superficial way to put the events of the twentieth century in context, then this book is not for you. But if what you seek is a way of building and interlinking your existing knowledge of the twentieth century then you will certainly not be disappointed by this amazing book.