The man who knew the way to the moon covered this.

Summary: Von Braun and the senior gang wanted an orbital staging platform and essentially milk the moon project for funding to do that because then you can go further with the same investment. However, the rockets needed were not available, and new rocket systems are rocket science, so you could not get to the moon by the time JFK wanted it. The lunar orbiter was the only thing that would likely work in the timeframe.

So they did the minimalistic moon project, funding dried up, and nobody built a good staging platform after because of lack of money.

John C Houbolt (NASA, Wiki) may be good starting points too.

Another for your Daughter's reading list: An astronaut's guide to life. And maybe in a few years, Project Paperclip, to keep hero worship in check.
Maybe also Surely you're joking Mr. Feynman, for general interest.