As the title indicates, if you are in the wine industry (at any point along the supply chain) or if you are considering entering the industry, read this book. If you are interested in learning how to taste wine, that is not the intent of this book. Lewis writes this book as an insider on the industry and from a consultant's perspective.
This book is a must read for anyone considering entering the wine business! Much of what Lewis writes could help fill out the majority of your business plan - from determining cash flows to gaining insight into the wine industry in general. Or at the least, you could use the book as a check on some of your assumptions.
If however, you simply want to learn how to taste & enjoy wine, you would do well to look for another book. His focus is purely from a business perspective.