This book is fantastic in its detailed effort to cover all aspects of midi orchestration that a modernist composer needs to know.
This book is perfect for composers who already have some technological proficiency with the likes of Logic or Cubase, and therefore can use this book to improve the final sound of their compositions.
Unlike other books that aim to improve the realism of a composition, this book successfully explains the requisites when writing for a certain instrument e.g. ranges, limitations etc. so that you do not get used to writing passages that might sound good but are unplayable in practice
I bought this book to help reduce the 'midi-like' quality of my compositions and I have to say that this book hits the nail on the head. Whether it's adding legato to a violin passage or panning different sections of the orchestra, this guide provides pretty much all the information you need to know.
This book, however, is not ideal for composers who have no prior knowledge of orchestration or instrumentation, as there are other books that are more suitable in giving you more detailed information in those areas.
Hope this helps!
p.s. The guide comes complete with a DVD to provide audio and image examples of what it being explained!