Many years later, I bought my own facsimile edition with illustrations by Jessie Wilcox Smith. I don't have that book anymore, but there's always the Internet to look at.
Also through the magic of the Internet I have unearthed some words by G.K.Chesterton about this wonderful tale. I hope you will humor me as I share a long, insightful quote. (It's from his introduction to George MacDonald and His Wife, by Greville MacDonald.)
"Of all the stories I have read....it remains the most realistic, in the exact sense of the phrase, the most like life. When I say it is like life, what I mean is this. It describes a little princess living in a castle in the mountains which is perpetually undermined, so to speak, by subterranean demons,who sometimes come up through the cellars. She climbs up the castle stairway to the nursery or other rooms, but now and again the stairs do not lead to the usual landings but to a new room she has never seen before and generally cannot find again. Here a good great-grandmother who is a sort of fairy godmother is perpetually spinning and speaking words of encouragement and understanding. When I read it as a child, I felt that the whole thing was happening inside a real human house not essentially unlike the house I was living in, which also had staircases and rooms and cellars. This is where the fairy tale differed from many other fairy tales. Above all, this is where the philosophy differed from many other philosophies. I have always felt a certain insufficiency about the ideal of progress....It hardly suggests how near both the best and worst things are to us from the first, even perhaps especially at the first. And though like every other sane person I value and revere the ordinary fairy tale of the miller's third son who sets out to seek his fortune, the very suggestion of setting off travelling to a far off fairy land prevents it from achieving this particular purpose of making all the ordinary staircases and doors and windows into magical things."