The sequel to Jean Webster's wildly charming Daddy Long-Legs.
Judy and Jervie have run off and gotten married. Sallie McBride has graduated from college and looking for a job. Judy and Jervie arrange to have her take over the management of the John Grier Home. As Sallie works to make a better orphanage and implement all of her wonderful ideas, she has the grumpy and change-averse Scottish doctor Doctor MacRae to content and spar with.
I loved it as a child, and it still holds up as quite charming. I particularly like Sallie McBride's fix-it, control-enthusiast character. (Because she is VERY FAMILIAR to me.)
However, I think I've figured out why this book is so hard to find and isn't readily in print. There are some pretty hard words about feeble-mindedness and genetics and wiping out the feeble-minded which are pretty shocking to a contemporary reader.