Thank you for your insight, e2efour. Yes, I agree with you that it's the kind of unnatural sentence you might get in an English lesson or in a reading book for children learning to read. That's the reason I asked the context. I want to know what context it can be used in.
Thank you for your insight, Ex-editor-san. Yes, in this context, it makes sence. I hope it is not too much to ask but could you let me ask you one more question. How about this one: He quietly enters the room. There is a desk by the window. On the desk is a book. He picks it up....
Does this verison sound more natural?:
I'm not ex-editor, but I agree that because the desk has been mentioned earlier, it would be more natural to put it at the beginning of the sentence. Old information is usually slotted at the beginning. I might even replace it with a pronoun: 'On it is a book'.