Lion Library (#LL84) second printing March 1956 paperback (copyright 1947.) Cover by Bob Maguire, 35 cent cover price, 153 pages. Condition is VG+: tight and square; spine has some faint marks or raised wrinkles - as printed, age tanning is mild and uniform; line next to spine and faint creases at left of cover and middle-bottom; back cover has a pair of 1" lines at upper left corner; light overall wear (see scan.) No stamps, marks, or writing - a clean copy (amazingly so for fifty years old.)

To Keep or Kill, a nice 50-year-old paperback mystery by Wilson Tucker - author of more than 20 books (half SF) who was also very active in SF fandom (mainly from the Thirties through the Seventies.) I will strongly recommend his The Lincoln Hunters from 1958, which was an Ace SF Special in the late Sixties. Tucker's output is divided between SF and mysteries (kinda like Fred Brown, but not as prolific.) Lion Library is a publishing house that has been home for other SF writers like Bradley or Farmer, and nice copies of this vintage are hard to find.

To Keep or Kill - [since I haven't read this, here's the back cover blurb]:
A sudden blast, shattering the night
Two men killed, a third crawling off to hide like a wounded animal in terror...
The only witness kidnapped by a beautiful murderess, guarded by a gigantic idiot and a savage dog...
And then, in a power-line tunnel below the city's streets, the most brutal, sickening violence of all...