Junior novels, which I think people sometimes dismiss as just 'kid stuff,' are actually these perfect little stepping stones. They're longer than picture books but still have that supportive structure—short chapters, accessible vocabulary, a clear plot. It’s like training wheels for longer fiction. My niece was stuck on early chapter books for ages, afraid of anything thicker, but a 'Percy Jackson' book finally clicked because it had that familiar pacing and white space on the page that didn't intimidate her. She finished it in a weekend, a book three times the size of anything she’d read before.
The confidence boost is the real thing. Finishing a whole, proper-looking novel makes a kid feel like a 'real reader,' and that feeling is addictive. They start picking up more without even being prompted. Plus, a lot of these series are heavily serialized, so if a child connects with the characters, they have a built-in motivation to keep going, which builds reading stamina almost without them noticing. The transitional phase from learning to read to reading to learn gets smoothed over.