I bought this book as a kind of primer on asset allocation. I really appreciate William Bernstein's effort to simplify the theory of asset allocation. He makes a highly mathematical area a much easier read for the reader, by doing his best to omit a lot of mathematical input.
This book makes the case for index fund investing instead of mutual fund investing, as well as for buy-and-hold investing over the long run.
He also shows the reader how to allocate assets and how to make the decision about asset classes to invest in using easy to follow steps.
I only gave it 4 stars because I feel that more could be done to improve the presentation of the area of asset allocation to lay readers.