This short book is essentially an enriched list of 45 examples of how companies have used big data analytics.  Marr sticks to high level generalities, and the book is in the spirit of light business journalism rather than detailed expositions that walk you through a successful big data implementation in detail.  However, private companies, and many government agencies are notoriously shy about their own data, so a high level view like this is often as much as you can get, and the book is useful as a spur to thinking.  Not much is said about how company X accomplished their project, but often enough is said that you can guess. And reading about other organizations’ big data efforts can make you think about what you might do in your own.  Plus, the book does reward the reader with nuggets of noteworthy detail. For example, did you know that Windows 10 assigns each user an “Advertising ID” that advertisers can use for more effective targeting of ads? Or that John Deere offers farmers a portal to collect and analyze the data collected from sensors on their tractors?  A practical guide or textbook it is not, but it is a perfect book to have on hand and dip into frequently from time to time.