The author states that it is important for children to know what came before in order that they can understand what they read in the newspapers today. This is as true now as at any time, and I find van Loon's goals commendable in other ways. Seeing history as a story is valuable for children; knowing that history is the story of ourselves should cause us to relate to the characters as living players rather than vague and strange names written on a page. In some of the early chapters, this is done more or less succesfully. As history progresses, though, man becomes more competent at keeping records, leaving us more names, and more confusion.
I think what this book suffers from, is that it tries to do too much. The span is too great, or it tries to tell about too many people in a particular era, or tries to simplify the context too greatly. For my children, I would choose a book with this sort of purpose (to create a fluid referential timeline in story form) for pretty young elementary children. But this book strangely drops names that that age would not identify, with little background with which to incorporate them into the story. Perhaps children in the 20's would have already known these names. But I rather doubt it. So, instead the age appropriateness of the book shifts into a range in which I would desire a deeper analysis of either particular periods of history, or particular individuals.
There is also a general feeling of disdain for religion that I don't find appealing for children, as well as editorializing interjected into the flow of events that end up convoluting the story by placing the end into the middle.
However, if as an adult, you received a sort of peicemeal approach to history, instead of flowing from early events into the modern, you may indeed find some value in this book, if only read in a cursory way. It does give you a world-wide scope of what is going on in many places at the same time.
If this had been the first Newbery book I'd read, I think I would have formed the opinion that the award was purposed to lead children to the books adults believe they should be reading, rather than books that are of outstanding quality that children desire to read. For my children, my goal is to encourage them to enjoy reading, while giving them quality and enjoyable literature. This book may be quality, but if I gave it to my kids (the nearly 10 and 7yos), I fear they'd cry!