Tolkien talade med detta i hans brev # 33 till sina utgivare på Allen och Unwin och noterade att tonen i LotR är väsentligt mörkare och "äldre" än Hobbits:
In the last two or three days, after the benefit of idleness and open air, and the sanctioned neglect of duty, I have begun again on the sequel to the ‘Hobbit’ – The Lord of the Ring. It is now flowing along, and getting quite out of hand. It has reached about Chapter VII and progresses towards quite unforeseen goals. I must say I think it is a good deal better in places and some ways than the predecessor; but that does not say that I think it either more suitable or more adapted for its audience. For one thing it is, like my own children (who have the immediate serial rights), rather ‘older’. I can only say that Mr Lewis (my stout backer of the Times and T.L.S.) professes himself more than pleased.
I Brev # 34 berättade han att han kände att LotR skulle vara " skrämmande " för att yngre barn som kanske har haft den tidigare Hobbits boken:
When I spoke, in an earlier letter to Mr Furth, of this sequel getting ‘out of hand’, I did not mean it to be complimentary to the process. I really meant it was running its course, and forgetting ‘children’, and was becoming more terrifying than the Hobbit. It may prove quite unsuitable. It is more ‘adult’ – but my own children who criticize it as it appears are now older.
och i hans brev # 131 talade han till den stora förändringen av stilen:
The generally different tone and style of The Hobbit is due, in point of genesis, to it being taken by me as a matter from the great cycle susceptible of treatment as a ‘fairy-story’, for children. Some of the details of tone and treatment are, I now think, even on that basis, mistaken. But I should not wish to change much. For in effect this is a study of simple ordinary man, neither artistic nor noble and heroic (but not without the undeveloped seeds of these things) against a high setting – and in fact (as a critic has perceived) the tone and style change with the Hobbit’s development, passing from fairy-tale to the noble and high and relapsing with the return.
och i hans brev # 163 till W.H. Auden kritiserar några av skrifterna i hobbiten som både ungdomsstil och juvenilia:
I went on after return; but when I attempted to get any of this stuff published I was not successful. The Hobbit was originally quite unconnected, though it inevitably got drawn in to the circumference of the greater construction; and in the event modified it. It was unhappily really meant, as far as I was conscious, as a ‘children’s story’, and as I had not learned sense then, and my children were not quite old enough to correct me, it has some of the sillinesses of manner caught unthinkingly from the kind of stuff I had had served to me, as Chaucer may catch a minstrel tag. I deeply regret them. So do intelligent children.
Om du vill ha en mer detaljerad (och väldigt hård) kritik av dina egna verk kan du inte göra det bättre än hans Brev # 215 till Allen och Unwin (vägrar att delta i ett symposium om "skrivande för barn":
When I published The Hobbit – hurriedly and without due consideration – I was still influenced by the convention that ‘fairy-stories’ are naturally directed to children (with or without the silly added waggery ‘from seven to seventy’). And I had children of my own. But the desire to address children, as such, had nothing to do with the story as such in itself or the urge to write it. But it had some unfortunate effects on the mode of expression and narrative method, which if I had not been rushed, I should have corrected. Intelligent children of good taste (of which there seem quite a number) have always, I am glad to say, singled out the points in manner where the address is to children as blemishes... The relation between The Hobbit and its sequel is I think this. The Hobbit is a first essay or introduction (consideration will admit I think that it is a very just point at which to begin the narration of the subsequent events) to a complex narrative which had been brewing in my mind for years. It was overtly addressed to children for two reasons: I had at that time children of my own and was accustomed to making up (ephemeral) stories for them; I had been brought up to believe that there was a real and special connexion between children and fairy-stories. Or rather to believe that this was a received opinion of my world and of publishers. I doubted it, since it did not accord with my personal experience of my own taste, nor with my observation of children (notably my own). But the convention was strong. I think that The Hobbit can be seen to begin in what might be called a more ‘whimsy’ mode, and in places even more facetious, and move steadily to a more serious or significant, and more consistent and historical. . . . . But I regret much of it all the same. . . . .