Gunard Hjertstedt, bilinen adıyla Day Keene, ABD'li romancı, kısa öykü yazarı ve radyo ve televizyon senaristi. Keene 50'den fazla roman yazdı ve radyo pembe dizileri Little Orphan Annie ve Kitty Keene, Inc.'in baş yazarıydı. Romanlarının birçoğu, Joy House (MGM, 1964) ve Chautauqua (The Trouble with Girls, 1969) olarak dahil olmak üzere filmlere uyarlandı.

Romanlar
1949 Evidence Most Blind
1949 Framed in Guilt
1951 Hunt the Killer
1951 My Flesh is Sweet 
T1951 o Kiss, or Kill 
1952 About Doctor Ferrel
1952 Home is the Sailor (Yalnız Adam)
1952 If the Coffin Fits
1952 Wake Up to Murder  (Cinayetten Cinayete)
1953 Mrs. Homicide 
1954 The Big Kiss-Off
1954 Homicidal Lady 
1955 The Passion Murders / Farewell to Passion 
1955 Who has Wilma Lathrop?
1956 Flight by Night
1956 Murder on the Side
1958 It's a Sin to Kill
1958 Passage to Samoa
1959 Dead Dolls Don't Talk
1959 Moran's Woman
1959 Take a Step to Murder
1959 Too Black for Heaven
1959 Too Hot to Hold
1960 Payola
1960 Sleep with the Devil
1960 World Without Men
1961 Chautauqua
1962 Seed Of Doubt
1963 Bye, Baby Bunting
1964 L.A. 46
1964 Notorious
1965 Carnival of Death
1965 Miami 59
1965 World Without Women (Leonard Pruyn ile)
1966 Chicago 11
1967 Acapulco G.P.O
1968 Guns Along the Brazos
1968 So Dead My Lovely
1970 Strange Witness