Authors with 10 or more pseudonyms

150 Edward Alexander Crowley [1875-1947]
68 Lauran Paine [1916-]
57 Donald S(ydney) Rowland [1928-]
45 E(dwin) C(harles) Tubb [1919-]
39 J(ohn) R(ussell) Fearn [1908-1960]
33 Arthur Leroy Kaser [1890-1956]
32 Robert Silverberg [1935-]
27 David Ernest Bingley [1920-]
27 John Creasey [1908-1973]
27 Victor George Charles Norwood
25 Harlan (Jay) Ellison [1934-]
21 (Gordon) Randall (Phillip David) Garrett [1927-1987]
21 (Henry) Kenneth Bulmer [1921-]
21 Georges Simenon [1903-1989]
20 C(yril) M. Kornbluth [1924-1958]
20 Frederick Schiller Faust [1892-1944]
20 Robert L(ionel) Fanthorpe [1935-]
19 Michael (Angelo) Avallone [1924-1999]
18 Henry Kuttner [1914-1958]
18 Roger Phillips Graham [1909-1965]
17 Ray(mond Douglas) Bradbury [1920-]
17 William Rotsler [1926-]
16 Edward (St. John) Gorey [1925-]
16 Frederik (George) Pohl [1919-]
16 John S(tephen) Glasby [1928-]
16 Ramón Felipe ... Alvarez-del Rey de Los Uerdes [1915-1993]
16 Robert (Augustine) W(ard) Lowndes [1916-]
16 Willis Todhunter Ballard [1903-1980]
14 (Drexel) Jerome (Lewis) Bixby [1923-1998]
14 Lee Floren
14 William E. Daniel Ross
13 Christopher (Robin) Nicole [1930-]
13 Edward L. Stratemeyer [1862-1930]
13 H(enry James O'Brien) Bedford-Jones [1887-1949]
13 H(oward) P(hillips) Lovecraft [1890-1937]
13 Richard S(harpe) Shaver [1907-1975]
12 Algirdas Jonas Budrys [1931-]
12 Charles H(orace) Snow [1877-1967]
12 Forrest J(ames) Ackerman [1916-]
12 Laurence James [1942-]
12 Milward Rodon Kennedy Burge [1894-1968]
12 R(eginald) A(lec) Martin [1908-71]
12 St. George (Henry) Rathbone [1854-1938]
12 Terry Williams Harknett [1936-]
12 William Edmund Butterworth [1929-]
11 Dean (Ray) Koontz [1945-]
11 Donald A(llen) Wollheim [1914-1990]
11 Harry Benjamin Whittington [1915-1989]
11 Henry John Keevil(l) [1914-1978]
11 Hugh Zachary [1928-]
11 John B. Harvey [1938-]
11 Philip José Farmer [1918-]
11 Trevor Dudley Smith [1920-1995]
10 (S.) Robert Tralins
10 Charles N(ewman) Heckelmann [1913-]
10 F(rank) C. Kneller
10 John Wyndham Parkes Lucas Beynon Harris [1903-1969]
10 P(aul) W. Fairman [1916-1977]