Index funds have become such a ubiquitous tool for investors that it’s easy to forget that they’re a relative newcomer on the financial scene. Here’s a good summary — a good read in itself — of a new book that promises to be a good longer look at the origins of stock index funds, their benefits and unintended consequences. “In ‘Trillions: How a Band of Wall Street Renegades Invented the Index Fund and Changed Finance,’ Robin Wigglesworth, the global finance correspondent at Financial Times, does an excellent job tracing the history of the index revolution, from its unassuming birth to the $26 trillion behemoth it is today,” writes Stephen Foerster, a finance professor and author in a column for Marker. “The book really shines when Wigglesworth takes us down the relatively untrodden path of how theory was turned into practice by telling the tales of the ‘motley crew of nerds’ and ‘iconoclastic geeks’ who had to battle within their organizations to start the index revolution.”