I recently finished a classic in child development: How Children Learn by John Holt. It reminded me a lot of Richard Feynman's writing, like Surely You're Joking Mr. Feynman!, because it was written as a collection of observations, stories, and lessons learned in very straightforward language. I loved the references to typewriters (which sound like really good objects for kids to explore) and other somewhat dated/classic items.
It seems like he was one of the first proponents of the natural abilities and curiosities of kids and giving them the opportunity to lead their own educational explorations. I can see how a lot of other more recent parenting authors have built upon his foundations.
My full notes on the book are below.