Your child already loves this. The one who reads you a fact about hippo milk before you've had coffee, who wants the records book for their birthday, who has never once asked what happens next in a story and does not intend to start. Any one of these works on its own. What this page is really for is telling you what's different about seven books that all look identical on a table, so you buy the right two instead of the same one twice.
Put these seven on a table and they look like one book printed seven times. They aren't, and knowing the difference is most of what this page is for. Three are National Geographic Kids working the same seam. Weird But True! 1 is the little pocket paperback, one fact per page, no explanations, and the best-value object here. Ultimate Weird but True 3 is the big glossy hardcover version of the same franchise, and its one real advantage is the Ultimate Secret Revealed spreads, which stop and explain why a fact is true. Those two overlap, and I'd pick one. 5,000 Awesome Facts 3 is the one that clusters: twenty-five facts about sloths in a row instead of one and then a swerve, which is what a child wants when an obsession is forming. Then the two annuals, and they're doing opposite things despite the shared reputation. Guinness is about who is the most, so it's numbers and competition and a child working out whether they could beat it. Ripley's is about how on earth is that real, so it's stories and photographs and no number to memorize. The last two are DK, and they're a different animal entirely. It Can't Be True! isn't trivia at all, it's scale drawn as a picture, the blue whale next to the pile of elephants that weighs the same. Did You Know? is questions and answers, and it's the youngest and quietest thing here. A child who devours the National Geographic three may find both DK books slow, and a child who loves the DK books may find the fact bursts thin. Watch which way yours leans.