Day 1. On whether the Americans should be allowed to add their own color illustrations to The Hobbit:
It might be advisable…to let the Americans do what seems good to them — as long as it was possible…to veto anything from or influence by the Disney studios (for all whose works I have a heartfelt loathing).
Day 2. Responding to the jacket-flap of The Hobbit that said: “Here again a professor of an abstruse subject is at play.”
A professor at play rather suggests an elephant in its bath.
Day 3. On C. S. Lewis’s high opinion of The Hobbit:
I must respect his opinion, as I believe him to be the best living critic until he turned his attention to me, and no degree of friendship would make him say what he does not mean: he is the most uncompromisingly honest man I have ever met!
Day 4. On the dull prospects of writing a sequel:
I cannot think of anything more to say about hobbits.
Day 5. On “the snag” that parents might think parts of The Hobbit would be “too terrifying for bedside reading”:
That snag appears in everything….The presence (even if only on the borders) of the terrible is, I believe, what gives this imagined world its verisimilitude. ….A safe fairyland is untrue to all worlds.
Day 6. Puzzling over how to continue writing about hobbits:
Goodness knows what will happen. Mr. Baggins began as a comic tale among conventional and inconsistent Grimm’s fairy-tale dwarves, and got drawn into the edge of it — so that even Sauron the terrible peeped over the edge. And what more can hobbits do? They can be comic, but their comedy is suburban unless it is set against things more elemental.
Day 7. December 19, 1937. 
I have written the first chapter of a new story about Hobbits — “A long expected party”….Merry Christmas.