When you're a very new reader, sounding words out and recognizing familiar ones is an achievement. When they form a story that lets you figure things out for yourself - like whether Little Bear is just pretending this time - then you can really feel accomplished.
When you're just a slightly less new reader, past the point where words are mysteries, the next challenge might be to think like a detective about the events in a story. When the author trusts you to solve the mystery on your own before turning to the back for Encyclopedia Brown's solution, that's a heady feeling.
Several days ago, we lost Little Bear's creator, Else Holmelund Minarik, and today, we lost Donald J. Sobol, creator of Leroy "Encyclopedia" Brown. Both authors' work is still popular; there's not much that's dated about learning to read.
Children's lit news has felt like an obituary round-up of late. It's worth remembering, though, that if we've lost quite a few great people, it's because we've always had a lot of great people.