Nice little meme started by The Mad Hatter (check out the link for more info on the Hatter & his collaborative project to review all the Masterworks).
How many have you read? Not necessarily in the Masterworks format, of course. List below the jump.
Roman numerals for hardcovers. Bottom of the list includes to-be-published titles. Bold means I've read it.
I - Dune - Frank Herbert
II - The Left Hand of Darkness - Ursula K. Le Guin
III - The Man in the High Castle - Philip K. Dick
IV - The Stars My Destination - Alfred Bester
V - A Canticle for Leibowitz - Walter M. Miller, Jr.
VI - Childhood's End - Arthur C. Clarke
VII - The Moon Is a Harsh Mistress - Robert A. Heinlein
VIII - Ringworld - Larry Niven
IX - The Forever War - Joe Haldeman
X - The Day of the Triffids - John Wyndham
1 - The Forever War - Joe Haldeman
2 - I Am Legend - Richard Matheson
3 - Cities in Flight - James Blish
4 - Do Androids Dream of Electric Sheep? - Philip K. Dick
5 - The Stars My Destination - Alfred Bester
6 - Babel-17 - Samuel R. Delany
7 - Lord of Light - Roger Zelazny
8 - The Fifth Head of Cerberus - Gene Wolfe
9 - Gateway - Frederik Pohl
10 - The Rediscovery of Man - Cordwainer Smith
11 - Last and First Men - Olaf Stapledon
12 - Earth Abides - George R. Stewart
13 - Martian Time-Slip - Philip K. Dick
14 - The Demolished Man - Alfred Bester
15 - Stand on Zanzibar - John Brunner
16 - The Dispossessed - Ursula K. Le Guin
17 - The Drowned World - J. G. Ballard
18 - The Sirens of Titan - Kurt Vonnegut
19 - Emphyrio - Jack Vance
20 - A Scanner Darkly - Philip K. Dick
21 - Star Maker - Olaf Stapledon
22 - Behold the Man - Michael Moorcock
23 - The Book of Skulls - Robert Silverberg
24 - The Time Machine and The War of the Worlds - H. G. Wells
25 - Flowers for Algernon - Daniel Keyes
26 - Ubik - Philip K. Dick
27 - Timescape - Gregory Benford
28 - More Than Human - Theodore Sturgeon
29 - Man Plus - Frederik Pohl
30 - A Case of Conscience - James Blish
31 - The Centauri Device - M. John Harrison
32 - Dr. Bloodmoney - Philip K. Dick
33 - Non-Stop - Brian Aldiss
34 - The Fountains of Paradise - Arthur C. Clarke
35 - Pavane - Keith Roberts
36 - Now Wait for Last Year - Philip K. Dick
37 - Nova - Samuel R. Delany
38 - The First Men in the Moon - H. G. Wells
39 - The City and the Stars - Arthur C. Clarke
40 - Blood Music - Greg Bear
41 - Jem - Frederik Pohl
42 - Bring the Jubilee - Ward Moore
43 - VALIS - Philip K. Dick
44 - The Lathe of Heaven - Ursula K. Le Guin
45 - The Complete Roderick - John Sladek
46 - Flow My Tears, the Policeman Said - Philip K. Dick
47 - The Invisible Man - H. G. Wells
48 - Grass - Sheri S. Tepper
49 - A Fall of Moondust - Arthur C. Clarke
50 - Eon - Greg Bear
51 - The Shrinking Man - Richard Matheson
52 - The Three Stigmata of Palmer Eldritch - Philip K. Dick
53 - The Dancers at the End of Time - Michael Moorcock
54 - The Space Merchants - Frederik Pohl and Cyril M. Kornbluth
55 - Time Out of Joint - Philip K. Dick
56 - Downward to the Earth - Robert Silverberg
57 - The Simulacra - Philip K. Dick
58 - The Penultimate Truth - Philip K. Dick
59 - Dying Inside - Robert Silverberg
60 - Ringworld - Larry Niven
61 - The Child Garden - Geoff Ryman
62 - Mission of Gravity - Hal Clement
63 - A Maze of Death - Philip K. Dick
64 - Tau Zero - Poul Anderson
65 - Rendezvous with Rama - Arthur C. Clarke
66 - Life During Wartime - Lucius Shepard
67 - Where Late the Sweet Birds Sang - Kate Wilhelm
68 - Roadside Picnic - Arkady and Boris Strugatsky
69 - Dark Benediction - Walter M. Miller, Jr.
70 - Mockingbird - Walter Tevis
71 - Dune - Frank Herbert
72 - The Moon Is a Harsh Mistress - Robert A. Heinlein
73 - The Man in the High Castle - Philip K. Dick
74 - Inverted World - Christopher Priest
75 - Kurt Vonnegut - Cat's Cradle
76 - H.G. Wells - The Island of Dr. Moreau
77 - Arthur C. Clarke - Childhood's End
78 - H.G. Wells - The Time Machine
79 - Samuel R. Delany - Dhalgren (July 2010)
80 - Brian Aldiss - Helliconia (August 2010)
81 - H.G. Wells - Food of the Gods (Sept. 2010)
82 - Jack Finney - The Body Snatchers (Oct. 2010)
83 - Joanna Russ - The Female Man (Nov. 2010)
84 - M.J. Engh - Arslan (Dec. 2010)
Looks like I'm at 53 (neat!). Mostly from my obsession with Ace Doubles. I suspect I'd bat something like .900 in the Fantasy and Crime Masterworks series, as I like those genres a bit more...
