Most of us know that reading to babies is a very good thing - it's tied to language and cognitive development, helps strengthen the parent-child bond, and gives us a welcome script when we're trying to get in our recommended 30,000 words a day without having to rap the Fresh Prince of Bel-Air theme song yet again. But for optimal benefits, it may not be enough to simply grab any board book or Thai takeaway menu and start rattling off the words. According to a new study, the type of book you read may make a big difference.