The Big Data Now anthology is relevant to anyone who creates, collects or relies upon data. It's not just a technical book or just a business guide. Data is ubiquitous and it doesn't pay much attention to borders, so we've calibrated our coverage to follow it wherever it goes. In the first edition of Big Data Now, the O'Reilly team tracked the birth and early development of data tools and data science. Now, with this second edition, we're seeing what happens when big data grows up: how it's being applied, where it's playing a role, and the consequences - good and bad alike - of data's ascendance.