Your child is done with slim chapter books and keeps eyeing the thick ones, then putting them back. This trail is how they get to carry one around. Start here, at the top, with the shortest — each one is a little longer and asks a bit more than the last, all the way up to a five-hundred-page brick they finish and then ask you for the sequel. Nobody jumps straight to the brick. They climb to it, and by the time they get there it doesn't look like a wall anymore.
Start here, at the top. Each one is a little longer and asks a bit more than the last, and that's the whole design. The Sorcerer's Stone is barely three hundred pages and reads faster than it looks, so it's the safest first thick book there is. By the last rung, Keeper of the Lost Cities is over five hundred pages and your child won't notice, because they've been training for it since rung one. One honest note about the middle: Percy Jackson's Greek Gods is no thicker than the two books before it, but the language steps up and the myths are the real, grown-up ones, so it's a step even though the spine looks the same. It's also the one book here you can read in bites — each myth stands on its own — which makes it a good breather right where the ladder gets steep. Let each rung feel easy before you climb to the next. There is no prize for rushing, and finishing the last one is the entire point.