The first thing I want to say about this book is if you don't want a detailed discussion of Language as opposed to history then this book is not for you. However, since this was one of the things I was looking to study it was perfect for me.
The book covers the following main ideas:
(1) Concise introductions to the discovery and composition of the Indo-European language family.
(2) The way the proto-language has been reconstructed.
(3) Its most basic grammar
(4) The interrelationships between the different language groups
(5) The temporal position of the Indo-European languages
(6) Some of the difficulties in reconstructing a proto-language.
(7) Semantic field of the Proto-Indo-European lexicon.
(8) An examination of mythology and possible homelands of the Proto-Indo-Europeans.
For me the most interesting chapters were the last two, as they talked about the mythology and religion and how they can be reconstructed, and the possible homelands of the Proto-Indo Europeans. Its amazing what you can get from the words of a language!