this is the best book I ever read on the market for Hololens developing, but I have to say, this book is not for junior c# developer, you have to have some solid .net foundation to understand the code the book introduced.
this book step by step uncovered how Hololens works on every core aspects, from the low level API to high level Holotoolkit, this is very valuable
if you ever read the book "Programming Windows" by Charles Petzold, you will know this book uncover every core aspects of windows programming.
this book <Microsoft HoloLens By Example> is Hololens' "Programming Windows",
the reason I only give 4 stars is for lots of small mistakes existing in the sample code in the book, but since I am a senior c# developer, I can easily fix these bugs and make the programming running. I do hope the author can carefully check the code before put them into book later
anyway, this is a great book, I hope the author can publish the next version since Holotoolkit has changed lots after the book is published