Sibyl Sue Blue, better known under its paperback title, Galactic Sibyl Sue Blue, is a science fiction detective novel by Rosel George Brown, originally published in hardcover by Doubleday in 1966.

[2] In the initial story, Blue investigates "a foreign virus that caused suicides",[3] leading to a confrontation with "the mass vegetable mind of a menacing planet, an aspirant dictator, and an ex-husband who has become part of the plant life".

[4] Judith Merril noted that the title heroine, far from being a sexless genre stereotype, was instead "the swingingest mama since -- well, since."

[5] Kirkus Reviews also praised Blue as "latter day mass madness with just enough new twists to intrigue the escapegoat".

[4] P. Schuyler Miller compared the heroine to Modesty Blaise, "older, with better sense and a better figure" and concluded "I hope we see more of her".