Pornokitsch

Gulliver's Travels by Jonathan Swift (1726)

The Castle of Otranto by Horace Walpole (1765)

Vathek by William Beckford (1786)

The Monk by Matthew Lewis (1796)

Frankenstein by Mary Shelley (1818)

Melmoth the Wanderer [1, 2, 3, 4] by Charles Maturin (1820) 

The Narrative of Arthur Gordon Pym of Nantucket by Edgar Allan Poe (1838)

A Christmas Carol by Charles Dickens (1843)

Wuthering Heights by Emily Bronté (1847)

Moby Dick by Herman Melville (1851)

Uncle Silas: A Tale of Bertram-Haugh by Sheridan Le Fanu (1864)

Alice's Adventures in Wonderland by Lewis Carroll (1865)

Through the Looking-Glass, and What Alice Found There by Lewis Carroll (1871)

Flatland by Edwin A. Abbott (1884)

She by H. Rider Haggard (1886)

The Strange Case of Doctor Jekyll and Mr. Hyde by Robert Louis Stevenson (1886)

The Twilight of the Gods by Richard Garnett (1888)

The Story of the Glittering Plain by William Morris (1891)

The Picture of Dorian Gray by Oscar Wilde (1891)

Dracula by Bram Stoker (1897)

The Turn of the Screw by Henry James (1898)

The Man Who Was Thursday by G.K. Chesterton (1908)

The House on the Borderland by William Hope Hodgson (1908)

Black Magic by Marjorie Bowen (1909)

Zuleika Dobson by Max Beerbohm (1911)

A Princess of Mars by Edgar Rice Burroughs (1911)

Tarzan of the Apes by Edgar Rice Burroughs (1912)

The Lost World by Arthur Conan Doyle (1912)

The Night Land by William Hope Hodgson (1912)

Herland by Charlotte Perkins Gilman (1915)

The Citadel of Fear [Audio] by Francis Stevens (1918) 

A Voyage to Arcturus by David Lindsay (1920)

The Worm Ouroboros by E.R. Eddison (1922)

The Haunted Woman [Audio] by David Lindsay (1922)

Lady Into Fox by David Garnett (1922)

A Man in the Zoo by David Garnett (1924)

The King of Elfland's Daughter by Lord Dunsany (1924)

The Ship of Ishtar by Abraham Merritt (1926)

The Trial by Franz Kafka (1925)

The Castle by Franz Kafka (1926)

Witch Wood by John Buchan (1927)

War in Heaven by Charles Williams (1930)

Turnabout by Thorne Smith (1931)

The Night Life of the Gods by Thorne Smith (1931) [No luck, but here's a clip from the 1935 film!]

Dwellers in the Mirage by Abraham Merritt (1932)

The Werewolf of Paris by Guy Endore (1933)

Lost Horizon by James Hilton (1933)

Northwest Smith by C.L. Moore (1933-1940) ["Julhi", "Nymph of Darkness", "Lost Paradise", "Yvala", "Song in a Minor Key", "The Tree of Life", "Quest of the Starstone", "Shambleau"]

Jirel of Joiry by C.L. Moore (1934-1939) ["Quest of the Starstone"]

The Circus of Dr. Lao by Charles G. Finney (1935) [Nope, but here's the trailer for the 1964 adaptation.]

Land Under England by Joseph O'Neill (1935)

Conan the Conqueror [Audio] by Robert E. Howard (1935-1936)

At the Mountains of Madness by H.P. Lovecraft (1936)

To Walk the Night by William Sloane (1937)

Roads by Seabury Quinn (1938)

The Once and Future King by T.H. White (1939-1977) [Disney's finest love story]

Slaves of Sleep by L. Ron Hubbard (1939)

Caravan for China by Frank S. Stuart (1939)

Fear by L. Ron Hubbard (1940)

Darker Than You Think by Jack Williamson (1940)

The Case of Charles Dexter Ward by H.P. Lovecraft (1941)

The Land of Unreason by Fletcher Pratt and L. Sprague de Camp (1941)

Conjure Wife by Fritz Leiber (1943)

The Book of Ptath by A.E. Van Vogt (1943) [Cameleopard?]

The Dark World by Henry Kuttner (1946) [That cover!]

The Valley of the Flame by Henry Kuttner (1946)

Titus Groan by Mervyn Peake (1946) [Great piece on Peake's work, from an exhibition in 2010]

Gormenghast by Mervyn Peake (1950)

Titus Alone by Mervyn Peake (1959)

The Exploits of Engelbrecht by Maurice Richardson (1946)

Mistress Masham's Repose by T.H. White (1946)

Adept's Gambit by Fritz Leiber (1947)

The Well of the Unicorn by Fletcher Pratt (1948)

You're All Alone by Fritz Leiber (1950)

The Dying Earth by Jack Vance (1950)

The Devil in Velvet by John Dickson Carr (1951)

The Tritonian Ring by L. Sprague de Camp (1951)

Three Hearts & Three Lions by Poul Anderson (1953)

The Sword of Rhiannon by Leigh Brackett (1953)

The Broken Sword by Poul Anderson (1954)

The Lord of the Rings by J.R.R. Tolkien (1954-1955) [The best scene from the best adaptation.]

The Golden Strangers by Henry Treece (1956)

The Great Captains by Henry Treece (1956) [This cover is good. But these are so much better.]

The Haunting of Hill House by Shirley Jackson (1959) [Trailer!]

Stormbringer by Michael Moorcock (1963)

The Serpent by Jane Gaskell (1963) [Me, on Gaskell, over at r/fantasy]

Atlan by Jane Gaskell (1965)

The City by Jane Gaskell (1966)

Some Summer Lands by Jane Gaskell (1977)

The Crystal World by J.G. Ballard (1964)

Black Easter by James Blish (1967)

The Day After Judgement by James Blish (1968)

Rosemary's Baby by Ira Levin (1967) [Spoiler!]

A Wizard of Earthsea by Ursula K. Le Guin (1968)

The Green Man by Kingsley Amis (1969)

Neither the Sea Nor the Sand by Gordon Honeycombe (1969)

The Philosopher's Stone by Colin Wilson (1969)

The Pastel City by M. John Harrison (1971)

The Infernal Desire Machines of Doctor Hoffman by Angela Carter (1972)

Red Shift by Alan Garner (1973)

The Compleat Enchanter by L. Sprague de Camp and Fletcher Pratt (1975)

The Alteration by Kingsley Amis (1976)

Our Lady of Darkness by Fritz Leiber (1977)

The Drawing of the Dark by Tim Powers (1979) [There are not a lot of books that have special, beer-inspired limited editions. This is one of them.]

The Sending by Geoffrey Household (1980)

The Colour of Magic by Terry Pratchett (1983)

The Light Fantastic by Terry Pratchett (1983)

The Businessman: A Tale of Terror by Thomas M. Disch (1984)

Hawksmoor by Peter Ackroyd (1985)

Expecting Someone Taller by Tom Holt (1987)

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If you're still looking for reading, try H.P. Lovecraft's selection of the best British and Irish horror (with links).