Where Exactly is the Great Green Room?

Goodnight Moon, in print more or less continuously since 1947, was a staple, not of my childhood but of my childrearing years. The child in question simply wouldn't sleep without it. The words are forever imprinted in my mind along with certain images, a mashup of reality and the pages of the book. Particular pillows, a wind-up turtle, and the objects in Clement Hurd's flat, blocky illustrations. Things that fit logically and others that were purely sensory, like the smell of rain in the desert as night fell.You either love this book or hate it. People spoof it and study it and draw mystifying conclusions and  interesting literary parallels. In the end, Aimee Bender suggests in this essay on writing lessons to be drawn from the book, the power of the great green room lies in the reader's mind.