SF Fred Saberhagen The Mask of the Sun 52110 NA Jennifer Sills Massage Parlor (1973) 52180 SF Robert Lory A Harvest of Hoodwinks / Masters of the Lamp (July 1970) 52207 SF Steve Perry Matadora (1986) 52400 SF John Brunner Meeting at Infinity 52470 SF Donald A. Wollheim (ed.) Men on the Moon 52560 SF Alan E. Nourse The Mercy Men 52740 WE L.P. Homes The Maverick Star (1969) 52975 SF Gerard F. Conway The Midnight Dancers 53151 SF John W. Campbell The Mightiest Machine 53167 SF Algis Budrys, Charles G. Waugh, and Martin Harry Greenberg (eds.) Space Dogfights (1992) 53183 SF John Varley Millennium 53299 SF Spider Robinson Mindkiller 53355 SF Ian Watson Miracle Visitors 53415 SF John T. Phillifent Hierarchies / Doris Piserchia Mister Justice (May 1973) 53503 SF Andrew J. Offutt The Mists of Doom 53540 SF George Zebrowski The Monadic Universe 53540 WE William E. Vance The Wolf Slayer / Brian Garfield (as Brian Wynne) Mr. Sixgun (1954) 53570 SF D. G. Compton The Missionaries (1972) 53587 SF Edgar Rice Burroughs The Monster Men 53588 SF Edgar Rice Burroughs The Monster Men 53591 SF Edgar Rice Burroughs The Monster Men 53701 SF Edgar Rice Burroughs The Moon Maid 53702 SF Edgar Rice Burroughs The Moon Maid 53703 SF Edgar Rice Burroughs The Moon Maid 53705 SF Edgar Rice Burroughs The Moon Maid 53719 SF Charles de Lint Moonheart (1984) 53753 SF Edgar Rice Burroughs The Moon Men 53756 SF Edgar Rice Burroughs The Moon Men 53780 SF John W. Campbell The Moon is Hell 54101 SF Andre Norton Moon of 3 Rings 54103 SF Andre Norton Moon of 3 Rings 54104 SF Andre Norton Moon of 3 Rings (July 1978) 54105 SF Andre Norton Moon of 3 Rings (May 1981) 54201 SF Thomas Burnett Swann Moondust 54325 NA Rona Randall Mountain of Fear (1971) 54378 NA Virginia Coffman Moura (1963) 54380 NA Virginia Coffman Moura (1963) 54460 NA Edgar Rice Burroughs The Mucker (1974) 54462 SF Edgar Rice Burroughs The Mucker (1914) 54484 SF Charles de Lint Mulengro: A Romany Tale (1985) 54500 SF Mark Adlard Multiface (1975) 55145 SF Fritz Leiber You're All Alone (1973) 55309 SF Fred Saberhagen The Mask of the Sun 56010 SF Gordon R. Dickson Naked to the Stars 56940 SF Leigh Brackett The Nemesis from Terra (1976) 57140 WE Ray Hogan New Gun For Kingdom City / The Shotgunner 57601