Richmal Crompton, William the Bad. Six people got this (or at least various similar titles), and there were no wrong guesses. The style is pretty distinctive.
2. Ought to have some testimonials...
T.H. White, The Sword in the Stone (part of The Once and Future King, hence the clue). This time nine people got it and there were no wrong guesses. However, life became more interesting with the next one.
3. Nogglewop.
G.K. Chesterton, Four faultless Felons. Three people got this, and there were wrong guesses of Evelyn Waugh and P.G. Wodehouse. The clue was by the same author, of course, and perhaps in a more distinctive style.
4. Two, who grasped their foreheads convulsively, were engaged in solving mathematical problems
Charles Dickens, Dombey and Son. It was generally agreed that this was Dickens, with 3 votes for Nicholas Nickleby, 2 for Dickens (unspecified) and 1 each for David Copperfield and Hard Times. Dan Timotin and Colin Bell managed to identify the actual book. However I was also offered Evelyn Waugh (Decline and Fall) and J.K. Rowling, for reasons that I do not need to explain.
5. And he had trudged through Yorkshire dales...
William Wordsworth, Peter Bell. 3 votes for Wordsworth and 2 (after the hint referring to the Lake District) for that well-known poet Wainwright. One of the Wordsworth faction thought it might be a parody of Wordsworth, which could be said about quite a lot of the poet's work, perhaps.
6. Would it were so in Afghanistan!
Kipling, The Jungle Book. Eleven people realised it was Kipling, and the only deviations were votes for Kim and In the Lines, instead of the actual story.
7. ...the essence of spirituality may be referred to the second predicable.
Oliver Goldsmith, The Vicar of Wakefield. Only Miranda Mowbray and Dan Timotin identified it, and there was a wrong guess of Leacock.
8. Litre and half litre--that's all we serve.
George Orwell, 1984. Eight people got this, one of whom expressed it as "Blair, the socialist one, I mean". I was also offered Beerbohm, H.G. Wells, John Wyndham and Chesterton's The Flying Inn.
9. Moses, Goliath, and the rest of the Apostles.
Benjamin Disraeli, Sybil. This was the hardest of all, and only Robin Boswell got it, and that was after the "Yes, Prime Minister" clue. It was not any of Bleak House, Henry Fielding, Shaw, Nathaniel Hawthorne (one interpretation of the clue) or Arnold Bennett.
10. Je me plaisois surtout aux mathématiques...
Descartes, Discours de la méthode. There were 5 votes for Descartes and 4 for Pascal, another known thinker.
11. ...the gates of Kandahar.
Oscar Wilde, Ave Imperatrix. Four people got this. I was also given Keats (because of the line ending in "surmise"), Kipling (the obvious wrong answer), and Wodehouse (because of the clue about the Empress). The title might be translated as "What ho, Empress!"
12. ...a woman is practising howling below-stairs...
Edward Lear (a letter). Four people got this. It could have been by Carlyle, Walter Scott, Mark Twain, Poe, or Joyce (who got 2 votes), but wasn't.
Alasdair Grant started well, but was soon overtaken by Miranda Mowbray. Dan Timotin got close by using a search engine (not actually forbidden), but the free drink goes to Miranda, next time I see her---which is about once every 10 years on average.
Jonathan Partington, 12.3.02, revised 11.9.03